INVERTERS! INVERTERS! INVERTERS!

MICHAEL INVERTER CIRCUIT

2010-11-11T09:29:00.001-08:00

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METAL DETECTOR CIRCUIT

2009-05-12T14:57:00.003-07:00

This design has not been called a GOLD detector as this name has been left for the more complex detectors that actually discriminate been gold and other metals. There is an enormous difference between detecting gold and ordinary metals (called base metals). How the detector work? The circuit is an oscillator and the way it keeps oscillating is due to positive feedback. This is the case with all oscillators and the component that provides the feedback is the 1n capacitor between the collector and emitter of the transistor. It may seem unusual that the transistor can be turned on via the emitter to keep it oscillating, but in fact it does not matter if the emitter or base receives a signal as the important factor is THE VOLTAGE DIFFERENCE between these two terminals.

If the base is kept fixed and the emitter voltage is reduced, the transistor sees a higher voltage between the base and emitter and it is turned ON harder. If the voltage on the emitter increases, the transistor turns OFF as the difference between the two is reduced. This is exactly what happens in this circuit. The 1n capacitor between the collector and emitter influences the voltage on the emitter to turn the transistor on and off. It does this by constantly monitoring the voltage on the tuned circuit and passing the change to the emitter. In this project, the TUNED CIRCUIT is the parallel components consisting of the inductor (the search coil) and the 1n capacitor across it. This is called an LC circuit in which the L is the inductance of the inductor in Henries (or mH or uH) and C is the capacitance of the capacitor in Farads (or uF or nF or pF). We start when the transistor turns ON and allows a pulse of energy to enter the tuned circuit (later you will see how the transistor turns on). The pulse of energy (current) starts by trying to entering both the coil and capacitor. You would think the coil has the smallest resistance but the capacitor is uncharged and presents a theoretical zero resistance and begins to charge. When a small voltage appears across it, you would think the coil would become the least resistance as it consists of only a few turns of copper wire.

METAL DETECTOR CIRCUIT

2009-05-12T14:57:00.001-07:00

Inverter 100W 12VDC to 220V by IC 4047 - IRF540

2009-04-11T17:24:00.001-07:00

Inverter 100W 12VDC to 220V by IC 4047 - IRF540

2009-04-11T17:21:00.001-07:00

This is inverter 100W circuit, use IC 4047 alike inverter 100W transistor I use Mosfet IRF540 instead Transistor 2N3055.
It good Idae, power output 100W from transformer 2-3A.
Read detail more in circuit.

Circuit DC24V to AC220V Inverter 300W by NE555,CA3130,MJ15003

2009-04-11T17:16:00.000-07:00

This is circuit Inverter 300, Input battery 24V to Output 220V 50Hz 300W.
Use Component IC 4027,NE555,CA3130,7805 and Transister MJ15003

Circuit Inverter 100W by IC 4047 + 2N3055

2009-04-11T17:07:00.001-07:00

Circuit Inverter 100W by IC 4047 + 2N3055

This circuit Inverter input 12V (battery 12V)
to out 220V 50HZ, Eesy circuit because less component to use.
It use IC 4047 (oscillator 50HZ) and
Power Transistor 2N3055 x 2 ,OUTPUT Power 100W.

12VDC Fluorescent Lamp Driver

2009-04-11T16:58:00.001-07:00

A number of people have been unable to find the transformer needed for the Black Light project, so I looked around to see if I could find a fluorescent lamp driver that does not require any special components. I finally found one in Electronics Now. Here it is. It uses a normal 120 to 6V stepdown transformer in reverse to step 12V to about 350V to drive a lamp without the need to warm the filaments.

Circuit diagram

Parts:
C1 100uf 25V Electrolytic Capacitor
C2,C3 0.01uf 25V Ceramic Disc Capacitor
C4 0.01uf 1KV Ceramic Disc Capacitor
R1 1K 1/4W Resistor
R2 2.7K 1/4W Resistor
Q1 IRF510 MOSFET
U1 TLC555 Timer IC
T1 6V 300mA Transformer
LAMP 4W Fluorescent Lamp
MISC Board, Wire, Heatsink For Q1

Notes:
1. Q1 must be installed on a heat sink.
2. A 240V to 10V transformer will work better then the one in the parts list. The problem is that they are hard to find.
3. This circuit can give a nasty (but not too dangerous) shock. Be careful around the output leads.

CMOS INVERTER USING 4047

2009-04-11T16:51:00.001-07:00

Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.

Circuit diagram

How to calculate transformer rating
The basic formula is P=VI and between input output of the transformer we have Power input = Power output
For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18..3 = 220v*1
So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.

INVERTER CIRCUIT USING 4047 IC(CMOS)

2009-04-11T16:47:00.000-07:00

SIMPLE INVERTER CIRCUIT USING ASTABLE MULTIVIBRATOR

2009-04-11T16:38:00.001-07:00

Part	Total Qty.	Description	Substitutions
C1, C2	2	68 uf, 25 V Tantalum Capacitor
R1, R2	2	10 Ohm, 5 Watt Resistor
R3, R4	2	180 Ohm, 1 Watt Resistor
D1, D2	2	HEP 154 Silicon Diode
Q1, Q2	2	2N3055 NPN Transistor (see "Notes")
T1	1	24V, Center Tapped Transformer (see "Notes")
MISC	1	Wire, Case, Receptical (For Output)

Notes

Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.

The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055's in the parts list can only handle 15 amps each.

Remember, when operating at high wattages, this circuit draws huge amounts of current. Don't let your battery go dead :-).

Since this project produces 120 VAC, you must include a fuse and build the project in a case.

You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.

This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

If you want to make 220/240 VAC instead of 120 VAC, you need a transformer with a 220/240 primary (used as the secondary in this circuit as the transformer is backwards) instead of the 120V unit specified here. The rest of the circuit stays the same. But it takes twice the current at 12V to produce 240V as it does 120V.

Tl494 AS USE TO SUBTITUTE FOR SG3524N

2009-04-11T16:20:00.000-07:00

INVERTER: An inverter is an electronics device that converts battery DC to an AC signal it is the same thing as an oscillator. The AC signal can be of various waveforms; sinusoidal, rectangular, square, saw tooth, etc. The type of waveform that we use in our industrial and domestic homes is a sinusoidal wave; this is the best waveform that can run our appliance with out any problem of over heat.

Most model produce a modified square wave. This waveform allow home owners to run 98% of the typical loads in a house such as fluorescent lights, TVs, stereos, vacuums and power tools. The few limitations include some type of electronic controls like dimmer, switches, sensitive electronics like laser printers and photocopiers, and some small rechargeable devices. Occasionally some of these products will not work, or even fail, with modified square wave power. Some appliances like microwave may be noisier and stereo equipment and TVs may have a slight hum or buzz with this type of inverter power.

Inverters that produces pure sine wave to mimic convectional grid power eliminates background noise so that all appliance, including electronics, work without problem. They are particularly suited for sensitive electronics found in some computers and higher quality sound equipment.

INVERTER FOR HOMES…

In large remote residences, particularly those using auxiliary generators, inverters can reduce the cost of power generator by up to 90%. Most inverters include a stand-by battery charger, so that when the generator is on, the batteries are automatically recharged. Once the generator is turned off, the inverter system powers the same AC circuits. Not only do you have quiet power available 24 hours a day, but in most cases the fuel savings alone can pay for the complete cost of the inverter system in less than a year!

WHY DO I NEED AN INVERTER?

Inverter converts DC battery power to standard AC power. They allow you to run regular 120V, 220VAC appliances; including TVs, computers, microwaves and power tools. With an inverter your AC loads are run off your batteries and they can be used any time of day and night - without a generator – and definitely during a utility power failure.

DESIGN OF AN INVERTER

When designing an inverter, the first thing that comes to mind is an oscillator circuit. An oscillator is an electronic device that converts battery DC to an AC signal. The AC signal produce are non sinusoidal – they are AC signals that shows a great deviation from sine/cosine waveform; square wave, rectangular wave, saw tooth wave, trapezoid wave, quasi sine wave, etc (are all complex waves). However, sine wave can be generated by using special kind of oscillators such as Wien Bridge, Hartley oscillator, RC oscillator, and other Radio frequency oscillators. This kind of wave is not very easy to generate.

The use of relaxation oscillators can produce square wave, quasi sine wave etc. Examples of these are the Multivibrators; Astable, Monostable, and the Bistable (flip- flop).

It is note worthy that it is the oscillator that produces the waveform signal for the inverter. So, the choice of oscillator matters.

THYRISTOR INVERTER

2009-04-11T16:12:00.001-07:00

THYRISTOR INVERTER

The principle and design of this kind of inverter is based on the class D commutation. The topology is also reliable and works on transformer less operation. This inverter circuit has the following advantages:

Capability of a wide range of frequency variation.
Capability of excellent voltage regulation
Low commutation losses
Low no load losses
Transformer less operation and therefore higher speed of response as well as higher full load operating efficiency.

The circuit diagram is shown below

Auxiliary Impulse Commutated Inverter

As shown above, the circuit consists of two main thyristors SCR1 and SCR2 two auxiliary thyristors SCR3 and SCR4, the feedback diodes D₁ andD₂ and the commutating circuit components L and C. The load R₁ is connected between the pole point P and centre tap of DC supply. In order to explain the detailed circuit operation it is assumed that the circuit has attained the steady state while operation. It is also assumed that thyristor SCR1 is conducting and the current is flowing through the load from right to left, through upper half of the DC supply (V/2). The capacitor C is charged to its maximum voltage V_cmax with right hand side plate being positive, as shown. Now any time SCR1has to be turned -- off, the anode is fired. The circuit consisting of C, L, T₁ and T₂ oscillates to reverse the charge across C. Thus, the net current through SCR1 is now the algebraic sum of the load current and the oscillatory cycle current. If the oscillatory cycle current is more than the load current, for a period of time higher than the turn off time t_offof the device, the thyristor SCR1 will turn off the diode D₁ in the mean time becomes forward biased. However, in case the charge across the plate of the capacitor is not fully reversed and SCR1 has recovered its blocking capability, the diode D1 will allow the oscillatory current to flow, helping C to reverse the charge. While the thyristor SCR1 is still conducting SCR2 is fired. The load current now transfers to SCR3 via SCR1, C and L, thereby helping the capacitor to develop its full charge in reversing direction (-V_cmax). As and when C is fully charged, the current through SCR1 dies down to zero. Thyristor SCR3 therefore turns off by itself. The load current now flows through SCR4 via the lower half of DC supply (V/2) from left to right. Thus, the direction of current through the load is reversed.

Any time when SCR2 is to be turned off, SCR4 is fired. The capacitor, which has been fully charged with –Vcmax across its plates, reverses through SCR3, SCR2 and L; thus pushing the oscillatory cycle current through SCR2 in the direction opposite to the load current. The commutation process repeats similar to that already described for commutation of SCR1. While SCR2 is still conducting fire SCR4 so as to make up the loss of charge across C (if any) during commutation of SCR2. As the end of this process when C is fully charged to Vcmax, the thyristor SCR2 turns off by itself, leaving SCR1 to continue conduction of current through the load from right to left. Thus, one complete cycle of operation is completed.

This inverter is very popular in all industrial applications and is therefore very widely used for variable speed drives.

MODIFIED SINGLE- PHASE Mc MURRAY INVERTER

The auxiliary impulse commutated inverter (also popularly known as Mc Murray inverter) discussed in the preceding sub-section is one of the circuit techniques that is used to generate the pulse width Modulated (PWM) voltage. The basic circuit can be used as a building block in either single phase as half bridge (to generate a square waveform) or as full bridge (to generate a quasi square waveform). The main objective to use this circuit as a full bridge is to generate a quasi square or stepped load voltage wave, rather than square wave. The later is preferred in an attempt to reduce harmonics in the output waveform.

The full bridge consists of two identical inverters. While inverter 1 consists ofT1 and T2 as its main thyristors; inverter 2 has its main thyristors as T3 and T4. The two half bridges inverter 1 and inverter 2 are independently fired with a phase displacement between the two. The stepped load voltage waveform obtained at the output of bridge inverter is shown below. Since the load is connected between the two poles P1 and P2, the voltage across the load results into a stepped (quasi square) waveform with much lower harmonic content as compared to that of the square wave inverter.

TRUE INVERTER POWER

2009-03-29T10:13:00.001-07:00

True inverter power=KVA Rating of Transformer * Power Factor.

For its losses, since it not a true sine wave, tita=90/2=45 degree.
Therefore, Power Factor=COS45=0.7071

True inverter Power=Transformer KVA RATING * COS45.
For 1KVA,
True inverter power=1000*COS45
True inverter Power=700W the require fuse rating will be
I=700/230=3.0A.

DEEP CYCLE BATTERY

2009-03-22T08:54:00.001-07:00

Deep Cycle Batteries

We stock The Concorde deep cycle AGM, Surrette, and Crown industrial and deep cycle batteries.

See what is available on our webstore.

Under Construction

Our Deep Cycle Battery FAQ is here. Recently updated.

Transformers and Autotransformers

2009-03-06T16:20:00.001-08:00

Transformers and Autotransformers

Monophase and threephase: from 50 VA to 80 kVA

Technical Characteristics

Our monophase and threephase transformers and autotransformers are designed to meet the following priority requirements:

	Insulation class E for overtemperature max 75°C with ambient temperature of 40°C max.
	The insulation is subjected to the dielectric strength test: 4 kV between the primary and secondary windings and 2.5 kV between these windings and the ground.
	The listed power refer to continuous working with power factor = 1 and frequency 50-60 Hz.
	Fullpower data always refer to the maximum voltage.
	For transformers having many secondary voltages has to be specified the drawing power on every voltage.
	The terminal boards eliminate the risk of accidental contact and are made of self-extinguishing material.
	COMPLIANCE WITH THE STANDARDS CEI 14-4/8

Insulation Transformers

Monophase: from 500 VA to 30 kVA - Trimonophase: from 3 kVA to 40 kVA - Threephase: from 3 kVA to 75 kVA

TS-8 10 kVA

Technical Characteristics

Our monophase and threephase insulation transformers are designed to meet the following priority requirements:

	Insulation class E for overtemperature max 75°C with ambient temperature of 40°C max.
	The insulation is subjected to the dielectric strength test: 5 kV between the primary and secondary windings and 2.5 kV between these windings and the ground.
	Antijamming screening between the primary and secondary windings.
	The listed power refer to continuous working with power factor = 1 and frequency 50-60 Hz.
	High efficiency (95%)..
	No induced harmonic distortion.
	COMPLIANCE WITH THE STANDARDS EN 61558-2-4

Commercial use of Renewable Energy

2009-03-06T07:41:00.001-08:00

Commercial use of Renewable Energy

Renewable energy represents a viable alternative to grid sourced electricity for most sections of Commerce and Industry. In all cases there is an environmental benefit to an appropriately installed system, in the majority of cases, the installation can show real cost and business benefits.

Solar Water Heating can be more appropriate for commercial activities where a regular supply of hot water is required during the daylight hours rather than the domestic environment where there is a need to balance storage of hot water for use in the morning and evening with generation during the day.

Electricity generated from solar electric panels is available during the hours of business, a Solar PV installation can be tailored to provide electricity up to the normal level of consumption, thus there is no requirement for export metering nor associated administration.

Perhaps the most appropriate installation would be Wind Turbines, in particular where there is a continuous process. Though the majority of energy might still be grid fed, 100% of the electricity from a tailored wind turbine system would supplant mains fed electricity. Thus the relative value of the per Kwh wind generated electricity would be the same as the 'delivered' value of mains electricity.

Though the capital cost of renewable energy installations might appear un-economic. For the business user there are grants and significant tax incentives.

BrightLightSolar has many years of experience in energy and utility cost management including understanding the grant application process and tax incentives available. We are able to provide a full service including identifying and sourcing additional funding, recommending and installing the most approriate renewable energy equipment

Telecommunications
As more areas are linked to the expanding GSM network the need for reliable, remote power increases.

The power required by GSM transmitters, receivers and Microwave links is reducing as technologies improve. This means that solar energy in this field is becoming more and more competitive and cost effective, especially as a carefully designed solar power system will provide uninterrupted power 365 days a year.

Systems of this type operate by charging a large battery bank when the sun shines. This stores energy for cloudy days and for operation at night time.

Regional solar data is used to provide monthly average forecasts for power output from the solar and using the worst solar month as a base line a system can be dsigned that will provide clean, reliable power to the equipment all year round.

Since each piece of equipment is slightly different in the way it operates and the precise amount of power it consumes, and because every area of the world has quite different sunshine levels, it is necessary to take each application on a case by case basis.

If you have a potential Telecoms application then we would be pleased to hear from you and would be happy to work with you to produce a solar power system engineered for your application. Please use the questionnaire provided to give all the relevant details.
Businesses around the world are discovering that solar can provide real advantages as a source of power generation.

If your business is located in an area that lacks a reliable supply of grid electricity, you should consider solar for your needs. Bright Light Solar Ltd has the technical and practical expertise to deliver cost-effective energy solutions to your business. Our systems can be used either by themselves or in conjunction with an alternative (but intermittent) energy source - such as grid electricity or diesel generation.

Please contact us for further details.

commercial comment

Businesses & Communities - Case Study

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SG3524N(PWM INVERTER IC)

2009-02-24T20:09:00.001-08:00

Sg3524N is a regulated pulse width modulator (PWM) power control circuitry with low stand-by current. PWM is a good sine wave approximation. Nearly all types of equipment will run on this signal. The IC incorporates all the functions required in the construction of a regulated power supply, inverter, or switching regulator on a single chip. They can be used as a control element for high power-output application.
The Sg3524 is designed for switching regulators of either polarity,transformer-coupled d.c to d.c converter, transformerless voltage doublers and polarity converter applications employing fixed frequency, pulse-width-modulation (PWM) techniques. The complementary output allows either single ended or push –pull application. Each device includes an on-chip regulator, error amplifier, programmable oscillator, pulse-steering flip-flop, two uncommitted transistors, a high –gain comparator and current limiting and shut down circuitry. The Sg3524 has operating temperatures between 00C to 700C.
This IC Sg3524 can operate at a maximum voltage of 40V, the collector output current is 100mA and reference output current 50mA with lead temperature of 2600C.

OPERATION OF SG3524N
The SG3524 is a fixed frequency pulse width modulation voltage regulator control circuit. The regulator operates at a fixed frequency that is programmed by one timing resistor RT and one timing capacitor CT. RT establishes a linear control of the output pulse duration(width) by the error amplifier. The SG3524 contains an on board 5V regulator that serves as a reference, as well as supplying the SG3524 internal regulator control circuitry by a resistor ladder network to provide a reference within the common-mode range of the error amplifier or external reference can be used.

A second resistor divider network senses the output and the error signal is amplified. This voltage is then compared to the linear voltage ramp at CT .. The resulting modulated pulse out of the high-gain comparator is then steered to the appropriate output transistor Q1 and Q2 by pulse –steering flip-flop, which is synchronously toggled by the oscillator output.
The frequency of oscillation is mathematically given, thus.
Fo =1.30/RT*CT
Where
RT is in kilo Ohms
CT is in micro Farad
F0 is the frequency in Hz

For the purpose of this project, CT and RT were carefully selected and calculated for a frequency of 50Hz.

THE OUTPUT CIRCUITRY
The Sg3524 contains 2 identical NPN transistors, the collector and emitters of which are uncommitted. Each transistor has anti-saturation circuitry that limits the current through the transistor to a maximum of 100mA for fast response.
There are wide varieties of output configurations possible when considering the application of Sg3524 as a voltage regulator control circuit. They can be segregated into 3 basic categories;
capacitor diode –coupled voltage multipliers
Inductor- capacitor-implemented single ended circuit.
Transformer-coupled.

HAPPY NEW YEAR!

2009-01-08T06:20:00.001-08:00

Happy new year to all my fans who have made this web a wonderful one.

INVERTERS AND OSCILLATORS

2009-01-05T19:40:00.001-08:00

INVERTER:
An inverter is an electronics device that converts battery DC to an AC signal it is the same thing as an oscillator. The AC signal can be of various waveforms; sinusoidal, rectangular, square, saw tooth, etc. The type of waveform that we use in our industrial and domestic homes is a sinusoidal wave; this is the best waveform that can run our appliance with out any problem of over heat.

INVERTER FOR HOMES…
In large remote residences, particularly those using auxiliary generators, inverters can reduce the cost of power generator by up to 90%. Most inverters include a stand-by battery charger, so that when the generator is on, the batteries are automatically recharged. Once the generator is turned off, the inverter system powers the same AC circuits. Not only do you have quiet power available 24 hours a day, but in most cases the fuel savings alone can pay for the complete cost of the inverter system in less than a year!

WHY DO I NEED AN INVERTER?
Inverter converts DC battery power to standard AC power. They allow you to run regular 120V, 220VAC appliances; including TVs, computers, microwaves and power tools. With an inverter your AC loads are run off your batteries and they can be used any time of day and night - without a generator – and definitely during a utility power failure.

When designing an inverter the power rating of the load is taken into consideration at maximum capacity. Choose a size that can power the appliance you plan to use. Typical sizes installed in our home systems are 1000W to 2500W. Larger inverters from 4KW to 11KW are used in large power systems and industrial applications. Inverters are rated according to the continuous power that they can produce; however, they are also designed to deliver large amounts of current for short period of time – a feature called surge capacity

DESIGN OF AN INVERTER
When designing an inverter, the first thing that comes to mind is an oscillator circuit. An oscillator is an electronic device that converts battery DC to an AC signal. The AC signal produce are non sinusoidal – they are AC signals that shows a great deviation from sine/cosine waveform; square wave, rectangular wave, saw tooth wave, trapezoid wave, quasi sine wave, etc (are all complex waves). However, sine wave can be generated by using special kind of oscillators such as Wien Bridge, Hartley oscillator, RC oscillator, and other Radio frequency oscillators. This kind of wave is not very easy to generate.

The use of relaxation oscillators can produce square wave, quasi sine wave etc. Examples of these are the Multivibrators; Astable, Monostable, and the Bistable (flip- flop).

It is note worthy that it is the oscillator that produces the waveform signal for the inverter. So, the choice of oscillator matters.

TRANSFORMER FOR INVERTER

2009-01-05T19:14:00.001-08:00

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> TRANSFORMER
> A transformer may be defined as a piece of apparatus
> without a continuously moving part which employs the
> principles of electromagnetic induction to transform
> alternating or intermittent voltage or current in one
> winding into alternating voltage or current in one or more
> windings, usually of different value of voltage or current.
> A transformer used to increase voltage of an a.c is called
> step up transformer while the one used to decrease voltage
> of an a.c is called step down transformer.
> Moreover, transformer can also be used to isolate one
> circuit from another, which ensures safety and guide against
> electric shock when working on the low side of an a.c.
>
> A transformer consists of laminated sheets made of silicon
> steel insulated from one another. This reduces eddy current
> loss. The vertical positions of the core are referred to as
> limb and the top and bottom positions are the yoke. Both the
> primary and secondary coils are wound on the limbs. The
> primary coil is connected to the a.c supply while the
> secondary is usually connected to the load.
>
> 2.15 TYPES OF TRANSFORMERS
> There are different types of transformers:
> 1. Single phase transformers
> 2. Three phase transformers
> 3. Auto-transformers
> 4. Current transformers
> 5. Voltage (or potential) transformers
> 6. Power transformers.
> Power transformers have a high utilization factor, that is,
> they are designed to run with almost constant load, which is
> equal to their rating or capacity.
> The maximum efficiency is designed to be at full load, this
> means that the full load winding losses must be equal to
> core losses.
> 2.16 TRANSFORMER COOLING
> When transformer is supplying power to a load, heat is
> generated in the winding and core due to losses. The heat
> dissipated due to losses should be transferred away from the
> winding and core of the transformer to avoid damage.
> The cooling methods used are:
> 1. Air cooled system: - The transformer casing is
> perforated on both sides. Air circulates through the unit by
> convention. This is usually confined to small transformer of
> the range 1KVA – 5KVA.
> 2. Oil –filled cooling system
> 3. Water cooled system
> 4. Air blast (force air) cooling system.

INTRODUTION TO INVERTER DESIGN

2009-01-05T19:00:00.001-08:00

Inverters are electronic circuits converting a D.C. power as a primary power source into A.C. power of predetermined frequency, amplitude and phase.
In principle, the parameters describing the resulting A.C voltage (frequency, amplitude, phase number, e.t.c.) can be arbitrarily chosen. In practice, single phase and three phase realization are most common. Frequency is limited by the dynamic behavior of the electric element chosen.
The pole changes required to turn out an A.C voltage is performed by means of suitably chosen electronic switching elements usually transistors or thyristors. Depending on the switching elements used, we have thus, a thyristor switching inverter and a transistor switching inverter.
Furthermore, due to elimination of mechanical contacts, transistor and /or thyristor inverters are not subject to wear, and there is no soot deposit. They are faster in term of switching speed, they are portable and are maintenance free.
Moreover, in designing inverter, the basic components; the simple diodes, transistors, the power MOSFETS, the thyristors, the transformers, and Battery are effectively utilized.
2.2 THE DIODE
A diode is a rectifying device, which permits current flow in one direction only, being able to withstand a potential difference without current flow in the opposite direction.
The active material from which the semi-conductor power diodes is formed is silicon, a semi-conducting material, that is, a material of which the conductivity is classified as being between insulating and conducting; its resistance decreases with temperature rise. The diode is a P-N junction device from which all other semiconductor components are made.
The N-type semiconductor has electrons (Negative charges) and P-type semiconductor has holes (Positive charges).

2.3 Operation of the P – N Diode
When the P-type is more positive with respect to the N-type by the application of voltage, the electrons in N-type are pulled to the side of P-type and hole is pulled to the side of N-type. In this way, the electric current flows through the semiconductors. And the diode is said to conduct. Conversely, when the N-type is made more positive with respect to the P-type, by the application of potential difference, electrons in N-type are pulled with positive voltage on the side of N-type and holes in the P-type are pulled with the negative voltage on the side of P-type. In this case, the electrons in the semiconductor do not move an so, the diode will not conduct and is said to be reverse biased.

INTRODUCTION TO UPS

2009-01-05T18:54:00.000-08:00

INTRODUCTION

The concept of Uninterruptible Power Supply (UPS) comes to mind because of the challenging problems we encounter in the Nigeria power system.
In Nigeria where we experience unpredicted power cut, voltage fluctuation, low voltage, etc, efforts has been made to substitute for existing power with an alternative power which is usually generator. This ensures that businessmen and other business organizations will be able to meet their customer's day to day needs and requirements in order to efficiently maximize profit.
However, the use of private generators has posed more problems to business men because of the inherent disadvantages associated with maintenance cost, repair due to wear of machine parts and cost of fueling the generator. This makes it exorbitantly expensive to run. Moreover, the noise associated with its operation is a nuisance to the neighborhood, a major source of pollution. Another more dangerous pollutant is the fume released to the atmosphere when the generator is in normal working operation. This is hazardous to the environment and society at large.
Consequently, because of the aforementioned disadvantages associated with generators own by individuals, the inverter provides a clean, noiseless, maintenance free power supply to run our domestic and commercial loads when there is utility failure. By incorporating automatic switching mechanism between utility and inverter, the UPS is defined. The UPS ensures that there is constancy of power to the system in use even if there is utility failure and supplies rated voltage and frequency to load even if utility voltage is low.
The inverter converts DC battery power to standard AC power. They allow us to run regular 230Vac appliances, including TVs, computers, microwave and power tools. Inverter can be used any time of the day and night.
Inverters are rated according to the continuous power that they can produce.. Moreover, for the purpose of this project, a 1KVA uninterruptible power supply (UPS) will be designed and constructed.
The UPS consist of the following incorporated systems:
1. Inverter system
2. Automatic battery charger with controller
3. battery monitor( to automatically disconnect load when battery is low)
4. Automatic voltage control(AVC)
5. Indicators/display to signal 1,2,&3
6. Auto transfer between utility power and inverter.

1.1 THE INVERTER SYSTEM
This converts DC battery voltage to alternating voltage AC. The AC voltage is an approximation of sine wave; it is the pulse width modulation type.

1.2 AUTOMATIC BATTERY CHARGER
This charges the battery immediately when utility power is restored. The charger is a two stage charger which provides a constant current until the battery reaches its rated capacity and then switches to a float voltage. The current then reduces as necessary to maintain the battery at the float voltage (trickle current).

1.3 THE BATTERY MONITOR
This is achieved by use of comparator. The comparator compares the output battery voltage with the input and when battery voltage goes below the set point, it automatically disconnects the load from battery so that battery is not completely flat.

1.4 INDICATOR/DISPLAY
It indicates normal working condition of the above features.

1.5 AUTO TRANSFER SWITCH
These are relay operated switches to automatically switch on/off load from utility to inverter or vice versa. When there is utility failure it switches automatically to inverter and when utility power is restored, it automatically switches from inverter to utility power.

1.6 AUTOMATIC VOLTAGE CONTROL (AVC)
This functions like a voltage regulator. It ensures that there is no much voltage variation from the preset desired value of 230V when load of its rated capacity is impressed on it. This makes the UPS unique.
Moreover, the design of the UPS requires a careful selection of semiconductor parts from the electronic data sheet, the power switching semiconductor device so chosen is the MOSFET. The power MOSFET has a positive temperature coefficient for resistance; hence, paralleling of the device is relatively simple. The popular IRF 150N is selected because it is more versatile, rugged and has a maximum drain current rated 40A, Vds 100V maximum. This component will be carefully mounted on an aluminium heat sink for heat dissipation during working condition.

Battery Safety Tips

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We must think safety when we are working around and with batteries. Remove all jewelry. After all you don't want to melt your watchband while you are wearing the watch. The hydrogen gas that batteries make when charging is very explosive. I have had 2 batteries blow up and drench me in sulfuric acid.. That is no fun. This is a good time to use those safety goggles that are hanging on the wall. Sulfuric Acid eats up clothing and you may want to select Polyester clothing to wear, as it is naturally acid resistant. I just wear junk clothes, after all Polyester is so out of style. When doing electrical work on vehicles it is best to disconnect the ground cable. Just remember you are messing with corrosive acid, explosive gases and 100's amps of electrical current.

Basically there are two types of batteries; starting (cranking), and deep cycle (marine/golf cart). The starting battery (SLI starting lights ignition) is designed to deliver quick bursts of energy (such as starting engines) and have a greater plate count. The plates will also be thinner and have somewhat different material composition. The deep cycle battery has less instant energy but greater long-term energy delivery. Deep cycle batteries have thicker plates and can survive a number of discharge cycles. Starting batteries should not be used for deep cycle applications. The so-called Dual Purpose Battery is only a compromise between the 2 types of batteries.

Wet Cell (flooded), Gel Cell, and Absorbed Glass Mat (AGM) are various versions of the lead acid battery. The wet cell comes in 2 styles; serviceable, and maintenance free. Both are filled with electrolyte and I prefer one that I can add water to and check the specific gravity of the electrolyte with a hydrometer. The Gel Cell and the AGM batteries are specialty batteries that typically cost twice as much as a premium wet cell. However they store very well and do not tend to sulfate or degrade as easily or as easily as wet cell. There is little chance of a hydrogen gas explosion or corrosion when using these batteries; these are the safest lead acid batteries you can use. Gel Cell and some AGM batteries may require a special charging rate. I personally feel that careful consideration should be given to the AGM battery technology for applications such as Marine, RV, Solar, Audio, Power Sports and Stand-By Power just to name a few. If you don't use or
operate your equipment daily; this can lead premature battery failure; or depend on top-notch battery performance then spend the extra money. Gel Cell batteries still are being sold but the AGM batteries are replacing them in most applications. There is a little confusion about AGM batteries because different manufactures call them different names; some of the popular ones are sealed regulated valve, dry cell, non-spillable, and sealed lead acid batteries. In most cases AGM batteries will give greater life span and greater cycle life than a wet cell battery.

SPECIAL NOTE about Gel Batteries: It is very common for individuals to use the term GEL CELL when referring to sealed, maintenance free batteries, much like one would use Kleenex when referring to facial tissue or "Xerox machine" when referring to a copy machine. Be very careful when specifying a battery charger, many times we are told by customer they are requiring a charger for a Gel Cell battery and in fact the battery is not a Gel Cell.

AGM: The Absorbed Glass Matt construction allows the electrolyte to be suspended in close proximity with the plateÕs active material. In theory, this enhances both the discharge and recharge efficiency. Actually, the AGM batteries are a variant of Sealed VRLA batteries. Popular usage high performance engine starting, power sports, deep cycle, solar and storage battery. The AGM batteries we sell are typically good deep cycle batteries and they deliver best life performance if recharged before the battery drops below the 50 percent discharge rate. If these AGM batteries are discharged to a rate of 100 percent the cycle life will be 300 plus cycles and this is true of most AGM batteries rated as deep cycle batteries.

GEL: The gel cell is similar to the AGM style because the electrolyte is suspended, but different because technically the AGM battery is still considered to be a wet cell. The electrolyte in a GEL cell has a silica additive that causes it to set up or stiffen. The recharge voltages on this type of cell are lower than the other styles of lead acid battery. This is probably the most sensitive cell in terms of adverse reactions to over-voltage charging. Gel Batteries are best used in VERY DEEP cycle application and may last a bit longer in hot weather applications. If the incorrect battery charger is used on a Gel Cell battery poor performance and premature failure is certain.

Battery Maintenance is an important issue. The battery should be cleaned using a baking soda and water mix; a couple of table spoons to a pint of water. Cable connection needs to be clean and tightened. Many battery problems are caused by dirty and loose connections. A serviceable battery needs to have the fluid level checked. Use only mineral free water. Distilled water is best. Don't overfill battery cells especially in warmer weather. The natural fluid expansion in hot weather will push excess electrolytes from the battery. To prevent corrosion of cables on top post batteries use a small bead of silicon sealer at the base of the post and place a felt battery washer over it. Coat the washer with high temperature grease or petroleum jelly (Vaseline), then place cable on the post and tighten. Coat the exposed cable end with the grease. Most folks don't know that just the gases from the battery condensing on metal parts cause most corrosion.

Introduction to Battery

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The commercial use of the lead acid battery is over 100 years old. The same chemical principal is being used to create energy that our Great, Great, Grandparents may have used.

If you can grasp the basics you will have fewer battery problems and will gain greater battery performance, reliability, and longevity. I suggest you read the entire tutorial, however I have indexed all the information for a quick read and easy reference.

A battery is like a piggy bank. If you keep taking out and putting nothing back you soon will have nothing.

Present day chassis battery power requirements are huge. Look at today's vehicle and all the electrical devices that must be supplied. Electronics require a source of reliable power. Poor battery condition can cause expensive electronic component failure. Did you know that the average auto has 11 pounds of wire in the electrical system? Look at RVs and boats with all the electrical gadgets that require power. I can remember when a trailer or motor home had a single 12-volt house battery. Today it is standard to have 2 or more house batteries powering inverters up to 4000 watts.

Average battery life has become shorter as energy requirements have increased. Life span depends on usage; 6 months to 48 months, yet only 30% of all batteries actually reach the 48-month mark. A Few Basics The Lead Acid battery is made up of plates, lead, and lead oxide (various other elements are used to change density, hardness, porosity, etc.) with a 35% sulfuric acid and 65% water solution. This solution is called electrolyte which causes a chemical reaction that produce electrons. When you test a battery with a hydrometer you are measuring the amount of sulfuric acid in the electrolyte. If your reading is low, that means the chemistry that makes electrons is lacking. So where did the sulfur go? It is resting to the battery plates and when you recharge the battery the sulfur returns to the electrolyte.

DC to AC Circuits and Inverter Circuits

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Converters:

12 Volt Automotive Inverter : This circuit will allow you to operate small devices like laptop computers inside your automobile without an expensive automobile power supply. The circuit takes advantage of the fact that power transformers are linear devices and can be used to step up as well as step down.

12 Volt DC to 120 Volt AC Inverter: this inverter should solve that problem. It takes12 VDC and steps it up to120 VAC. The-Wattage depends on which transistors you use for Q1 and Q2, as well as how "big" a transformer you use for T1. The inverter can be constructed to supply anywhere from1 to1000 (1 KW)-Watts.

DC to AC Inverter:

Digital to Analog Centronics D / A & Filter:

High Power 12 V to 300 V Inverters for High Repeat rate medium Power Strobes: runs on12 V, at up to 6 A, and can fire the tubes at a rate of about 8-10 Times per second.

Tiny Tiny Inverter Design: little efficient circuit that runs off of3V, and charges up a little1 uf250-Volt cap all the way up in about30 seconds

Various Schematics and Diagrams

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Contents:

Chapter 1) About the Author & Copyright
Chapter 2) Introduction
Chapter 3) Simple High Voltage Generator
Chapter 4) Adjustable High Voltage Power Supply
Chapter 5) Panasonic VCR Switching Power Supply (PV48XX and Clones)
Chapter 6) Variable Intensity Variable Frequency Stroboscope
Chapter 7) Jacobs Ladders
Chapter 8) Inverter Circuits
8.1) Super simple inverter
8.2) Notes on super simple inverter
8.3) Archer mini flashlight fluorescent lamp inverter
8.4) Notes on Archer mini flashlight fluorescent lamp inverter
8.5) Energizer mini flashlight fluorescent lamp inverter
8.6) Notes on Energizer mini flashlight fluorescent lamp inverter
8.7) Pocket fluorescent blacklight inverter GH-RV-B1
8.8) Notes on Pocket blacklight inverter
8.9) Low power fluorescent lamp inverter 1
8.10) Notes on low power fluorescent lamp inverter 1
8.11) Low power fluorescent lamp inverter 2
8.12) Notes on low power fluorescent lamp inverter 2
8.13) Medium power fluorescent lamp inverter
8.14) Notes on medium power fluorescent lamp inverter
8.15) Basic 200 W power inverter
8.16) Notes on basic power inverter
Chapter 9) Kevin's Strobe Schematics
9.1) High power inverter and trigger circuits
9.2) Tiny tiny inverter design
Chapter 10) IR Detector/Tester Circuits
10.1) IR detector circuit using bare photodiode
10.2) IR detector circuit using IR receiver module
Chapter 11) Basic Incandescent Light Dimmer Circuits
11.1) Simplest dimmer schematic
11.2) 3-way dimmer schematics
11.3) Simple 3-way dimmer schematic 1
11.4) Simple 3-way dimmer schematic 2
11.5) Independent dimming from two locations - kludge #3251
Chapter 12) Simple Power Supplies
12.1) Converting an AC output wall adapter to DC
12.2) Adding an IC regulator to a wall adapter or battery
Chapter 13) Discrete Multivibrator Schematic
Chapter 14) Ultrasonic cleaner schematic
Chapter 15) Range, oven, and furnace electronic ignition Schematic
Chapter 16) Bug Zapper
Chapter 17) Electronic Air Cleaner HV Generator
Chapter 18) Auto Air Purifier HV Generator
Chapter 19) Typical Rechargeable Flashlight Schematics
19.1) First Alert Series 50 rechargeable flashlight schematic
19.2) Black & Decker Spotlighter Type 2 rechargeable flashlight
19.3) Brand Unknown (Made in China) rechargeable flashlight schematic
Chapter 20) Interesting Sequential Neon Flasher
[Document Version: 1.61] [Last Updated: 05/25/1998]

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Chapter 2) Introduction

This is a collection of various useful and interesting schematics. Some
of these are also referenced by or included in other documents at this site.

What isn't here (this may not be everything):

* Extremely important safety information. See the document: "Safety Guidelines for High Voltage and/or Line Powered Equipment". Many of these
circuits involved high voltage and/or direct line-connected high power
systems. Getting electrocuted could ruin your whole day. For really high
voltage equipment, also see: Tesla Coils Safety Information.

* Laser power supplies and other laser related schematics will be found in
the document: "Lasers: Safety, Diode Lasers, Helium Neon Lasers, Drive,
Info, Links, Parts".

* Additional electronic flash and other strobe related schematics will be
found in the document: "Notes on the Troubleshooting and Repair of Electronic Flash Units and Strobe Lights and Design Guidelines, Useful Circuits, and Schematics".

* Isolation and variable transformers (Variacs), homemade degaussing coils,
series light bulb adapter, and other Incredibly Handy Widgets(tm) for your
test bench will be found in the document: "Troubleshooting and Repair of
Consumer Electronic Equipment" and possibly in the specific document for
each type of equipment.

* General nifty gadget and other pack rat stuff can be found in the document:
"Salvaging Interesting Gadgets, Components, and Subsystems" which identifies
useful components which may be removed from common consumer electronics and
appliances as well as unconventional uses for their subsystems, modules, or
replacement parts.

* Schematics associated with the testing of capacitors, transistors and other
semiconductor devices (includes simple curve tracer design), flyback
transformers, etc., will be found in the document dealing with each of
these typse of devices.

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Chapter 3) Simple High Voltage Generator

This basic circuit is capable of supplying up to 30 kilovolts or more
from a low voltage DC source using a flyback (LOPT) transformer salvaged
from a TV or computer monitor. Typical output with a 12 VDC 2 A power
supply or battery will be around 12,000 V. Current at full voltage is
typically around 1 to 2 mA. Higher currents are available but the output
voltage will drop. At 2 KV, more than 10 mA may be possible depending on
your particular flyback transformer.

This is an ASCII file: F_hvinvert.html

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Chapter 4) Adjustable High Voltage Power Supply

This circuit uses a pair of 555 timers to provide variable frequency variable
pulse width drive to an inverter using a flyback transformer salvaged from
a black and white or color TV or computer monitor.

The input voltage can range from about 5 to 24 V. Using a flyback from a MAC
Plus computer which had its bad primary winding excised, an output of more than
20 KV is possible (though risky since the flyback is probably not rated for
more than about 12 KV) from a 24 VDC, 2 A power supply. By adjusting the drive
frequency and duty cycle, a wide range of output voltages and currents may
be obtained depending on your load.

With the addition of a high voltage filter capacitor (.08 uF, 12 KV), this
becomes a nice little helium neon laser power supply which operates on 8 to
15 VDC depending on required tube current and ballast resistor. See the
document: "Lasers: Safety, Drive, Info, Parts; Diode, HeNe, Ar/Kr Ion Lasers"
for details.

The drive transformer is from a B/W computer monitor (actually a video display
terminal) and has a turns ratio of 4:1 wound on a 5/16" square by 3/8" long
nylon bobbin on a gapped ferrite double E core. The primary has 80 turns and
the secondary has 20 turns, both of #30 wire. Make sure you get the polarity
correct: The base of the switching transistor should be driven when the driver
turns on.

Where the flyback includes an internal rectifier and/or you are attempting
to obtain the maximum output voltage of a specific polarity, the direction of
drive matters as the largest pulse amplitude is generated when the switching
transistor turns off. Since flyback transformers are not marked, you will
have to try both possible connections to the drive coil. Use the one that
produces the higher output voltage for a given set of input conditions (drive
and pulse rate/width).

Many variations on this basic circuit are certainly possible. However, one
nice thing about running it at 24 VDC or less is that it is much more difficult
to let the smoke out of the circuit! The 5 A power supply I was using shut
down on several occasions due to overcurrent but the only time I blew the
chopper transistor was by accidentally shorting the base to collector.

These schematics are available in both PDF and GIF format.

Get HVGEN32-SCH: hvgen32.pdf or hvgen32.gif

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Chapter 5) Panasonic VCR Switching Power Supply (PV48XX and Clones)

This circuit was reverse engineered from the switching power supply from
a Panasonic VCR. It is typical of the small switchers used in the Panasonic
PV28XX, PV48XX, and many other models, their Magnavox clones, as well as other
Matsushita manufactured VCRs. Many VCRs of other brands use similar designs.

Errors in transcription are possible. Some models use additional outputs each
fed from a single rectifier diode and filter capacitor (not shown). Some part
numbers and the connector pinout may not be the same for your particular VCR.

A totally dead supply with a blown fuse usually means a shorted switchmode
power transistor, Q1. Check all other components before applying power
after replacement as other parts may be bad as well.

The most common problems resulting in low or incorrect outputs are dried
up or leaky electrolytic capacitors - C4, C16, C17, C21.

See the document: "Notes on the Troubleshooting and Repair of Small Switchmode Power Supplies" for more info.

These schematics are available in both PDF and GIF format:

Get VCRPS-SCH: vcrps.pdf or vcrps.gif

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Chapter 6) Variable Intensity Variable Frequency Stroboscope

The circuit referenced in the document: Notes on the Troubleshooting and
Repair of Electronic Flash Units and Strobe Lights and Design Guidelines,
Useful Circuits, and Schematics" is designed to provide a variety of options
in terms of repetition rate, flash intensity, and various repeat and
triggering modes.

The design includes:

* Line operated voltage doubler power supply.

* Power transformer operated low voltage logic supply.

* Variable frequency repeat mode controlled by 555 timer.

* Optoisolated external trigger input.

* Selectable flash intensities of .2, 2, and 20 W-s.

* Autorepeat speeds from .05 to 100 Hz (though obviously, the flashlamp will
not operate at all intensities for these entire ranges.)

Parts of this circuit have been built and tested but the entire unit is not
complete. Maybe someday....

These schematics are available in both PDF and GIF format.

Get STROBEX-SCH: strobex.pdf or strobex.gif

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Chapter 7) Jacobs Ladders

The climbing arcs of old bad sci-fi movies are always a popular item. Just
make sure you understand the safety implications before constructing one of
these. See the document: "Safety Guidelines for High Voltage and/or Line Powered Equipment".

This is an ASCII file: F_jacobs.html

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Chapter 8) Inverter Circuits

Except for the "Super simple inverter", these circuits were all reversed
engineered from commercial products. The good news is that this means they
probably all work somewhat reliably. The bad news is that a custom wound
transformer (you can build in most cases) will be needed and there may be
errors in the number of turns and wire sizes listed since these were all
determined without totally dismembering the unit in question.

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8.1) Super simple inverter

This circuit can be used to power a small strobe or fluorescent lamp. It will
generate over 400 VDC from a 12 VDC, 2.5 A power supply or an auto or marine
battery. While size, weight, and efficiency are nothing to write home about -
in fact, they are quite pitiful - all components are readily available (even
from Radio Shack) and construction is very straightforward. No custom coils
or transformers are required. If wired correctly, it will work.

Output depends on input voltage. Adjust for your application. With the
component values given, it will generate over 400 V from a 12 V supply and
charge a 200 uF capacitor to 300 V in under 5 seconds.

For your less intense applications, a fluorescent lamp can be powered directly
from the secondary (without any other components). This works reasonably well
with a F13-T5 or F15-T12 bulb (but don't expect super brightness). Q1 does
get quite hot so use a good heat sink.

C1 1 uF D2 1N4948 R2
+------||------+ T1 1.2KV PRV 1K 1W
| | +-----|>|-----/\/\---+------o +
| R1 4.7K, 1W | red ||( blk |
+-----/\/\-----+------+ ||( |
| yel )||( +_|_ C2
+ o----------------------------------+ ||( --- 300 uF
| red )||( - | 450 V
| +--------------+ ||( |
| Q1 | ||( blk |
6 to 12 | |/ C +--------------------+------o -
VDC, 2A +----| 2N3055 Stancor P-6134
D1 _|_ |\ E 117 V Primary (blk-blk)
1N4007 /_\ | 6.3 VCT Secondary (red-yel-red)
| |
- o------------+------+

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8.2) Notes on super simple inverter

1. Construction can take any convenient form - perf board, minibox, etc.
Make sure the output connections are well insulated.

2. C1 must be nonpolarized type - not an electrolytic.

3. D1 provides a return path for the base drive and prevents significant
reverse voltage on the B-E junction. Any 1 A or greater silicon diode
should be fine.

4. C2 is shown as typical energy storage capacitor for strobe applications.
Remove D2 and C2 for use with a fluorescent lamps.

5. D2 should be a high speed (fast recovery) rectifier. However, for testing,
a 1N4007 should work well enough. R2 limits surge current through D2.

6. The polarity of the input with respect to the output leads is important.
Select for maximum voltage by interchanging the black output wires.

7. Mount Q1 (2N3055) on a heat sink if continuous operation is desired. It
will get warm. Other NPN power transistors with Vceo > 80 V, Ic > 2 A,
and Hfe > 15 should work. For a PNP type, reverse the the polarities of
the power supply and D1, and interchange one set of leads (where a diode
is used for DC output).

8. Some experimentation with component values may improve performance for
your application.

9. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by R1 and C1 (and the gain of your particular
transistor).

10. WARNING: Output is high voltage and dangerous even without large energy
storage capacitor. With one, it can be lethal. Take appropriate
precautions.

11.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

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8.3) Archer mini flashlight fluorescent lamp inverter

The circuit below was reverse engineered from the Archer model number 61-3724
mini fluorescent/incandescent flashlight combo (no longer in the Radio Shack
catalog). The entire inverter fits in a space of 1-1/8" x 1" x 3/4". It is
powered by 3 C size Alkaline cells and drives a F4-T5 tube.

This design can easily be modified for many other uses at lower or higher
power.

o T1
+ o----+----------+----------------+ o
| | )|:| +--------------+-+
| \ D 28T )|:|( | |
| R1 / #26 )|:|( +|-|+
| 560 \ +---------+ |:|( | - |
| / | |:|( O 315T | | FL1
| | | o |:|( #32 | | F4-T5
| +------|---------+ |:|( | - |
| | | )|:|( +|-|+
+_|_ C1 | | F 28T )|:|( | |
--- 47 uF | | #32 )|:| +--------------+-+
- | 16 V | | +---+
| | | Q1 | O = Output
| | C \| | D = Drive
| C2 _|_ |---+ F = Feedback
| .022 uF --- E /| |
| | | _|_ C3
| | | --- .022 uF
| | | |
o-----+----------+------+-----+

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8.4) Notes on Archer mini flashlight fluorescent lamp inverter

1. T1 is an E-core ferrite transformer. The core is 5/8" x 3/4" x 3/16"
overall. The outer legs of the core are 1/8" thick. The central leg
is 3/16" square. The square nylon bobbin has a diameter of 5/16". There
is a .020" gap (spacer) in between the two halves of the E-core.

The 315T O (Output) is wound first followed by the 28T D (Drive) and 28T F
(Feedback) windings. There should be a strip of mylar insulating tape
between each of the windings.

The number of turns were estimated without disassembly as follows:

* The wire sizes were determined by matching the diameters of the visible
ends of the wire for each winding to magnet wire of known AWG.

* The number of turns in the Output winding was determined based on its
measured resistance, core diameter, and the wire gauge tables.

* A 50 KHz .1 V p-p signal was then injected into the Feedback winding.
The amplitudes of the resulting outputs from the Drive and Output
windings were then measured. From these, the ratios of the number of
turns were calculated.

2. The transistor was totally unmarked. A general purpose NPN medium power
transistor like a 2N3053 or ECG24 should work. For PNP types, reverse the
polarities of the power supply and C1.

Since it is very low power, no heat sink is used in the Archer flashlight.
However, for other applications, one may be needed.

3. Some experimentation with component values may improve performance for
your application.

4. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by C2 and C3, the number of turns on each of
the windings of T1, and the gain of your particular transistor.

5. WARNING: Output is high voltage and dangerous. Take appropriate
precautions.

6.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

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8.5) Energizer mini flashlight fluorescent lamp inverter

The circuit below was reverse engineered from the Energizer model number
unknown (worn off) mini fluorescent/incandescent flashlight combo. The entire
inverter fits in a space of 1-1/8" x 1-1/8" x 3/4". It is powered by 4 AA
size Alkaline cells and drives a F4-T5 tube.

This design is very similar to the Archer model (see the section: "Archer mini flashlight fluorescent lamp inverter", but eases starting requirements by
actually heating one of the filaments of the T5 lamp. Thus, a lower voltage
transformer can be used.

o T1 o
+ o----+----------+--------+-------------------+ |:| +----------------+
| | C4 _|_ )|:|( H 16T #32 |
| \ 1000 --- D 32T )|:| +--------------+ |
| R1 / pF | #26 )|:|( | |
| 360 \ +-------------------+ |:|( +|-|+
| / | |:|( | - |
| | | o |:|( O 160T | | FL1
| +--------|-------------------+ |:|( #32 | | F4-T5
| | | )|:|( | - |
+_|_ C1 | | F 16T )|:|( +|-|+
--- 47 uF | | #26 )|:|( | |
- | 16 V | | Q1 +---+ |:| +--------------+-+
| | | MPX9610 |
| | C \| R2 | O = Output
| C2 _|_ |---+---/\/\--- D = Drive
| .047 uF --- E /| | 22 F = Feedback
| | | _|_ C3 H - Heater (filament)
| | | --- .01 uF
| | | |
o-----+----------+--------+-----+

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8.6) Notes on Energizer mini flashlight fluorescent lamp inverter

1. T1 is an E-core ferrite transformer. The core is 1/2" x 5/8" x 3/16"
overall. The outer legs of the core are 3/32" thick. The central leg
is 3/16" square. The square nylon bobbin has a diameter of 5/16". There
is a .010" (estimate) gap (spacer) in between the two halves of the E-core.

The 160T O (Output) is wound first followed by the 16T H (Heater), 32T D
(Drive), and 16 T F (Feedback) windings. There should be a strip of mylar
insulating tape between each of the windings.

The number of turns were estimated after unsoldering the transformer from
the circuit board as follows:

* The wire sizes were determined by matching the diameters of the visible
ends of the wire for each winding to magnet wire of known AWG.

* The number of turns in the Output winding was determined based on its
measured resistance, core diameter, and the wire gauge tables.

* A 100 KHz .1 V p-p signal was then injected into the Drive winding. The
amplitudes and phases relationship of the resulting outputs from the
Feedback, Heater, and Output windings were then measured. From these,
the ratios of the number of turns and winding start/end were determined.

2. The transistor was an MPX9610. I was not able to locate specs for this
part number but a transistor like a 2N3053 or ECG24 should work. For PNP
types, reverse the polarities of the power supply and C1.

Since it is very low power, no heat sink is used in the Energizer
flashlight. However, for other applications, one may be needed.

3. Some experimentation with component values may improve performance for
your application.

5. WARNING: Output is high voltage and dangerous. Take appropriate
precautions.

6.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

8.7) Pocket fluorescent blacklight inverter GH-RV-B1

(Schematic from: Axel Kanne (axel.k@swipnet.se)).

This was reverse engineered from a toy pocket blacklight, made in China.
It has been tested with tubes up to 6 W.

4.5 to 12V (4) T1(2)
+ o---+-------------------+---------------+ +-----+-+
| | R2 )||( | |
| +--/\/\--+ W1 )||( +|-|+
| 470 | )||( | - |
+_|_ C1 +-----|------+ ||( W3 | | FL1
--- 47uF |/ C _|_ C3 ||( | | (3)
| 16V +---+------| Q1 --- .015 ||( | - |
| | | (1)|\ E | uF ||( +|-|+
| C2 _|_ | | +------+ ||( | |
| .01uF --- | R1 | | W2 )|| +--+--+-+
| | +--/\/\--|-----|------+ |
| | 20 | | |
- o---+---------+------------+-----+--------------+

--------------------------------------------------------------------------------

8.8) Notes on Pocket blacklight inverter

1. The original transistor is marked 8050 C0ZC. A 2N3055 works better than
the original, the tube starts faster and the transistor runs much cooler.

2. T1 is a ferrite E-core transformer measuring 17mm x 15mm x 15mm. The core
seems to be 5 mm thick. The turns ratio has not been determined. Winding
W1 is made of ~0.2 mm wire, the resistance is below 1 ohm. The data for
winding W2 is the same as winding W1. Winding W3 is made of ~0.5 mm wire
and its resistance is 5 ohms.

3. The original tube is an F4T5BLB blacklight tube, but the inverter has been
tested with an ordinary F4T5 tube as well as a Philips 6W tube. The 6W tube
causes the original transistor to run quite hot, so using a 2N3055 or
similar power NPN is recommended.

4. 4.5V seems to be the absolute minimal voltage required to start an F4T5
tube. 5V will start the 6W tube when a 2N3055 transistor is used. Voltage
can probably be cranked up above 12V, but that was the highest I tried
(Didn't want to test when the tube blows).

5. CAUTION: The inverter can give a nice(?) shock when run with the original
transistor on 5V. With a 2N3055 and higher supply voltage, it can be nasty.
Avoid touching the tube terminals. The bottom of the PCB can also give
quite suprise, as I discovered :-(.

6.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

8.9) Low power fluorescent lamp inverter 1

The circuit below was reverse engineered from a model number FL-12 'Made
in Hong Kong' battery (8 AA cells) or 12 V wall adapter powered portable
fluorescent lamp. The bulb is an F8-T5.

This design can easily be modified for many other uses at lower or higher
power. Note that its topology is similar to that of the circuit described
in the section: "Super simple inverter".

C2 .01 uF
+------||------+ T1 3
| | +------------+-+
| R1 1.5K | 4 o ||( | |
+-----/\/\-----+------+ ||( +|-|+
| 15T F )||( | - |
| 1 )||( | | FL1
+ o-----+----------|---------------------+ ||( O 350 T | | F8-T5
| | )||( | |
| | 20T D )||( | |
| R2 / 2 )||( | - |
| 68 \ +-------+------+ ||( +|-|+
6 to 12 _|_ C1 / Q1 | | ||( 5 | |
VDC --- 100 uF | | | +---+--------+-+
| 16 V | |/ C | |
| +----| 5609 +---------------+
| C3 _|_ |\ E NPN O = Output
| .027 uF --- | D = Drive
| | | F = Feedback
- o-------+----------+------+

--------------------------------------------------------------------------------

8.10) Notes on low power fluorescent lamp inverter 1

1. T1 is an E-core ferrite transformer. The core is 5/8" x 3/4" x 3/16"
overall. The outer legs of the core are 3/32" thick. The central leg is
3/16" square. The square nylon bobbin has a diameter of 5/16". There is
no visible spacer between the cores but I did not disassemble to confirm.

The 350T O (Output) is wound first followed by the 25T D (Drive) and 18T F
(Feedback) windings. There should be a strip of mylar insulating tape
between each of the windings.

The number of turns were estimated without disassembly as follows:

* The resistances of each of the windings was measured to determine the
arrangement of the transformer.

* The inverter was run at just enough input voltage for it to oscillate
(so the load of the fluorescent tube would not affect the readings) and
the voltages on all 3 windings were measured on an oscilloscope.
From this, the ratios for the windings were determined.

* An estimate was made of the number of turns likely to be on the Drive
winding based on other similar designs. The number of turns on the
other windings were calculated based on the turns ratios. Wire size
is probably #36 AWG.

2. The transistor was marked 5609 which I could not cross to anything. I
would guess that a general purpose medium NPN power transistor like a 2N3053
or ECG24 should work. For a PNP type, reverse the polarities of the
power supply and C1.

Since it is very low power, no heat sink is used in this lamp. However,
for other applications, one may be needed.

3. Some experimentation with component values may improve performance for
your application.

4. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by C2, C3, R1, R2, the number of turns on each
of the windings of T1, and the gain of your particular transistor.

5. WARNING: Output is high voltage and dangerous. Take appropriate
precautions.

6.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

8.11) Low power fluorescent lamp inverter 2

The circuit below is the type used in inexpensive fluorescent camping lanterns.
In this particular model, an F6-T5 lamp was used. It will drive F4-T5 to
F13-T5 tubes depending on input voltage. The power source can be a 4 to 9 V,
2 A power supply (depending on the size of your lamp) or a suitable battery
pack. This design was reverse engineered from a random commercial unit of
unknown manufacture using a lead-acid battery battery that expired long ago.

o T1
+ o----+---------+-------------------+
| | )|:| o C2
| S1 | D 20T )|:| +-------||-----+-+
| Start |- #26 )|:|( .022 uF | |
| | )|:|( 600 V +|-|+
| | +-------+ |:|( | - |
| R2 \ | |:|( O 250T | |
| 270 / | o |:|( #32 | | FL1
| \ +------|-------+ |:|( | | T5 lamp
+_|_ C1 | | | F/S 7T )|:|( | |
--- 100 uF | | | #32 )|:| +-------+ | - |
- | 16 V +----|------|---+---+ | +|-|+
| | | | | | |
| | | +-----------------|------+-+
| | +-----------+ |
| S2 | | | | O = Output
| _|_ Off | |/ C | | D = Drive
+-- --+--------+----| Q1 | | F/S = Feedback/starting
| | | |\ E 2SC1826 _|_ D2 |
| \ _|_ | /_\ 1N4007 |
| R1 / D1 /_\ | | |
| 220 \ 1N4148 | | | |
| | | | | |
o-----+-----+--------+------+-----------+---------+

The approximate measured operating parameters are shown in the chart below.
The two values of input current are for starting/running (starting is with
the Start button, S1, depressed.

Lamp type ---> F4-T5 F6-T5 F13-T5
V(in) I(in) I(in) I(in)
-------------------------------------------------------------
3 V .9/.6 A - -
4 V 1.1/.7 A 1.1/.8 A -
5 V 1.3/.8 A 1.2/.9 A -
6 V - 1.4/1.0 A 1.6/.95 A
7 V - - 1.7/1.0 A
8 V - - 1.8/1.2 A
9 V - - 2.1/1.3 A
10 V - - 2.2/1.4 A

--------------------------------------------------------------------------------

8.12) Notes on low power fluorescent lamp inverter 2

1. Construction can take any convenient form - perf board, minibox, etc.
Make sure the output connections are well insulated.

2. T1 is assembled on a square nylon bobbin, 3/8" cubed. Wind the 250T O
(Output) first, insulate with mylar tape, 20T D (Drive) next, and 7T F/S
(Feedback/Starting) last. Observe directions of windings as indicated by
the dots (o). The number of turns for the O winding was estimated based
on measured winding resistance, wire size, and the dimensions of the bobbin.

The core is just a straight piece of ferrite 1/4" x 1/4" x 1-3/8" It is
fully open - there is no gap.

3. Any general purpose NPN power transistor with Vceo > 80 V, Ic > 2 A, and
Hfe > 15 should work. For a PNP type, reverse the polarities of the power
supply, C1, D1, and D2.

Use a good heat sink for continuous operation at higher power levels (6 V
input or above). The type used (2SC1826) was a replacement after I fried
the unidentified transistor originally installed (103-SV2P001).

4. Pushbutton switches are used to control operation. S1 (Start) provides
initial base drive to the transistor via the Feedback/Starting winding of
T1 until the tube arc is established. At that point, feedback is sustained
via current flowing through the tube. S2 (Off) shorts the base of the
transistor to ground to stop the oscillator.

Like a regular manual start preheat fluorescent fixture, the start switch,
must be depressed until the lamp comes on at full brightness indicating that
the filaments are adequately heated.

5. Some experimentation with component values may improve performance for
your application.

6. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by R1 and R2 (during starting in particular),
the number of turns on each of the windings of T1, and the gain of your
particular transistor.

7. WARNING: Output is high voltage and dangerous. Take appropriate
precautions.

8.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

8.13) Medium power fluorescent lamp inverter

This circuit is capable of driving a variety of fluorescent lamps from a 4 to
12 V, 2 to 2.5 A DC power supply, rechargeable battery pack, or auto or marine
battery. With appropriate modifications (if needed) it may be used for other
applications like powering an electronic flash or HeNe laser tube. The
transformer will need to be custom wound (by you) but this is not really
difficult - just slightly time consuming for the 600 turn O (Output) winding
if you don't have a coil winding machine.

I have used it with fluorescent tubes of many sizes: F6-T5, F13-T5, F15-T12,
and F20-T12. The arc will be sustained with the filaments hot on an input
as low as about 3.5 to 4 V (with a new tube) but during starting, an input
voltage of about 5 or 6 V may be needed until the filaments are hot enough
to sustain the arc at the lower voltage.

Two nearly identical circuits are shown.

* This design saves a couple of diodes but requires a centertapped feedback
winding on the transformer. The input voltage must exceed about 4 V for
oscillation to commence:

+Vcc o T1
o Q1 +----------------+
| | )|:|
+ B |/ C )|:|
L1 |:|( +------| MJE3055T )|:| C1
24T |:|( | |\ E D 15T )|:| +----------||---------+-+
#22 |:|( | | #26 )|:|( .0039 uF | |
+ | -_- )|:|( 600 V +|-|+
| | )|:|( | - |
+--|-------------------------+ |:|( | |
| | )|:|( | |
| | Q2 _-_ )|:|( | |
| | | )|:|( O 600T | | FL1
| | B |/ E D 15T )|:|( #32 | |
| | ----| MJE3055T #26 )|:|( | |
| | | |\ C )|:|( | |
| | | | )|:|( | |
| | | +----------------+ |:|( | - |
| | | |:|( +|-|+
| | | o |:|( | |
| | -----------------------+ |:| +---------------------+-+
| | F 10T )|:|
| | #32 )|:|
| | +---------+ |:| O = Output
| | | F 10T )|:| D = Drive
| | | #32 )|:| F = Feedback
| +-------------------------+
| |
| R1 | R2
+----------/\/\/\--+--/\/\/\--+
220 22 _|_
1 W 2 W -

* The following slightly modified design starts oscillating at a very low input
voltage (under 2 V). This may be beneficial when driving small lamps. The
circuit behaves quite similarly in all other respects.

+Vcc o T1
o Q1 +----------------+
| | )|:|
+ B |/ C )|:| C1
L1 |:|( +---+----| MJE3055T )|:| +----------||---------+-+
24T |:|( | __|__ |\ E D 15T )|:|( .0039 uF | |
#22 |:|( | _/_\_ _|_ #26 )|:|( 600 V +|-|+
+ | _|_ - )|:|( | - |
| | - D1 1N4148 )|:|( | |
+--|---------------------------+ |:|( | |
| | _-_ D2 1N4148 )|:|( | |
| | __|__ _-_ )|:|( O 600T | | FL1
| | _\_/_ | )|:|( #32 | |
| | | B |/ E D 15T )|:|( | |
| | +----| MJE3055T #26 )|:|( | |
| | | |\ C )|:|( | |
/ | | | )|:|( | - |
R1 \ | | Q2 +----------------+ |:|( +|-|+
1K / | | |:|( | |
\ | | o |:| +---------------------+-+
| | +-----------------------+ |:|
| | F 10T )|:| O = Output
| | R2 22, 2 W #32 )|:| D = Drive
+--+---------/\/\/\------------+ F = Feedback

The switching frequency is about 21 KHz and varies less than 5 percent over
the range of input voltage for which the bulb remains lit (it is significantly
higher with no load - about 140 KHz). An input voltage of about 4 V is needed
to start oscillation (reducing R1 or increasing R2 would lower this at the
expense of efficiency at higher voltages) but it will continue well below 3 V.

The measured input current at various input voltages for two lamp types are
shown in the chart below. SV (Starting Voltage) is the minimum input voltage
required to preheat the filaments before the lamp will turn on (current is
lower until filaments are hot). FB (Full Brightness) is the point at which
the lamp appears to be operating at the same intensity as if it were installed
in a normal 115 VAC fixture.

Lamp type ---> F13-T5 F20-T12
V(in) I(in) I(in)
---------------------------------------------------
3 V - 1.37 A
4 V 1.76 A 1.52 A (SV)
5 V 1.80 A (SV) 1.60 A
6 V 1.90 A 1.65 A
7 V 1.96 A (FB) 1.70 A
8 V 2.02 A 1.80 A
9 V 2.16 A 1.90 A
10 V 2.33 A 2.05 A
11 V - 2.30 A (FB)
12 V - 2.60 A

--------------------------------------------------------------------------------

8.14) Notes on medium power fluorescent lamp inverter

1. T1 is an E-core ferrite transformer. Once complete, the cores are installed
on the bobbin with a 2 mm gap. Some experimentation with the core gap may
be needed to optimize performance for a given lamp type and input voltage.

Each E core is 1" x 1/2" x 1/4" overall. The outer legs of the core are
1/8" thick. The central leg is 1/4" square. The square nylon bobbin has
a diameter of 5/16" and length of 3/8".

The 600T O (Output) is wound first followed by the 15T D (Drive) and 10T F
(Feedback) windings. For convenience, wind the D and F windings bifiler
style (the two wires together). Determine the appropriate connections
with an ohmmeter (or label the ends). The centertaps are brought out to
terminals. Try to distribute the O winding uniformly across the entire
bobbin area by winding it in multiple layers. This will assure that no
wires with a significant voltage difference are adjacent. There should be
a strip of insulating tape between the O and the other windings.

2. L1 isolates the power supply. It is 24 turns of #22 wire wound on a 1/4"
ferrite core. The inverter works fine without L1 but seems to have a tad
more strength at low voltage with it.

3. The transistors are MJE3055T (2N3055 in a TO220 package) types but are not
critical. However, I expect that some faster switching transistors would
run cooler. Any fast switching NPN power transistor with Vceo > 80 V,
Ic > 3 A, and Hfe > 15 should work. For PNP types, reverse the polarity
of the power supply.

For operation above about 6 V, a pair of good heat sinks will be required.
However, power dissipation in the transistors does not seem to increase
as much as expected - the base drive is probably more optimal at higher
input voltage.

4. Some experimentation with component values may improve performance for
your application.

5. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by C1, the number of turns on each of the
windings of T1, the gap of the core of T1, and the gain of your particular
transistor. If the circuit does not start oscillating, interchange the
F winding connections to Q1 and Q2.

6. WARNING: Output is high voltage and dangerous. Take appropriate
precautions.

7.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

8.15) Basic 200 W power inverter

This circuit was reverse engineered from a Tripp-Lite "Power-Verter" Model
PV200 DC to AC Inverter - typical of those used for camping or boating
applications where the only source of power is an auto or marine battery.
This particular model is rated 200 W continuous. The output is a 60 Hz
squarewave and there is no regulation or precise frequency control. (Unlike
the other circuits in this collection, it is NOT a high frequency inverter.)

Modifications for higher or lower output voltage are easily achieved. For
example, a fast cycle strobe requiring 330 VDC, would only require using three
times the number of turns on the Output winding and the addition of a bridge
rectifier to charge the energy storage capacitor(s). Alternatively, the
inverter could be used as-is with the addition of a voltage tripler. A tripler
rather than doubler is needed because of the squarewave output. (The RMS and
peak voltages are the same so you don't get the boost of 1.414 as you do with
the sinusoidal waveform from the power company.)

3 o
+12 VDC +--------+--------------+
o | | )||
| |/ C +_|_ C1 )||
S F1 20 A +------| Q1 --- 10 uF 31T D )|| o 2
| | |\ E -_|_ 160 V #13 )|| +---------o AC Hot
\ S1 | _|_ - )||(
| Pwr | - )||(
| | 4 )||(
+------+---|--------------------------------+ ||(
| | | _-_ )||(
| | | | )||( O 360T
| | | |/ E _-_ C2 31T D )||( #20
| / | ----| Q2 -_|_ 10 uF #13 )||(
C3 +_|_ R3 \ | | |\ C --- 160 V )||(
10 uF --- 150 / | | | + | 5 )||(
50 V - | 5 W \ | | +--------+--------------+ ||(
| | | | ||( 1
| | | +---------------------+ || +------o AC Neutral
| | | | 6 o ||
+------+---|-------------------+ +-------+ || T1
| | F 17T )||
| R3 2.7 10 W | #24 7 )|| O = Output
| +----/\/\----+------------+ || D = Drive
| |R2 2.7 10 W 10 o || F = Feedback
| +----/\/\-----------------+ ||
| _|_ F 17T )|| (Pin numbers from
| - #24 8 )|| Triplite unit.)
+--------------------------------+

--------------------------------------------------------------------------------

8.16) Notes on basic power inverter

1. Construction was all done point-to-point - there is no circuit board.
Layout appears not to be critical.

2. T1 is a relatively large heavy laminated E-I core transformer. The E and I
sheets alternate direction to assure a low reluctance magnetic circuit.

The core dimensions are 3-3/4" x 3-1/8" x 1-1/8" overall. The outer legs
of the core are 5/8" thick. The central leg is 1" wide. The square bobbin
has a diameter of 1-3/8".

The 360T O (Output) secondary is wound first as 4 or 5 insulated layers
followed by the 31T D (Drive) and 17T F (Feedback) windings. There are
insulating layers between each of the windings.

The number of turns were estimated without disassembly as follows:

* The wire sizes were determined by matching the diameters of the visible
ends of the wire for each winding to magnet wire of known AWG and/or
measuring with a micrometer where possible. (The Drive windings are
actually wound using square cross-section magnet wire for maximum packing
density. This was estimated to be equivalent to #13 AWG round wire.)

* The number of turns in the Output winding was determined based on its
measured resistance, core diameter, and the wire gauge tables.

* The inverter was run and the amplitudes of the signals on each winding
were measured. From these ratios, the number of turns were calculated.

2. The transistor were marked 69-206. ECG29 is a close match - high power
amplifier switch - 80 V, 50 A, 300 W, Hfe 20 min. 2SD797 is another
readily available power transistor that should work. For PNP types,
reverse the polarities of the power supply, C1, C2, and C3.

The transistors are mounted on heat sinks which form the sides of the case.

3. C3 and R3 are required for starting. Since there is no source of current
for the bases of the transistors other than the Feedback windings, this
provides a starting pulse to Q2 when the unit is switched on. Ramping the
input voltage slowly rather than using the power switch would likely result
in the inverter behaving like an inanimate object.

4. Measured frequency of operation was about 56 Hz. This is likely affected
by nearly everything - input voltage, capacitance, core saturation, phase
of the moon, etc. Therefore, don't expect to drive a clock mechanism from
this thing with any accuracy!

5. Some experimentation with component values may improve performance for
your application.

6. When testing, use a variable power supply so you get a feel for how much
output voltage is produced for each input voltage. Component values are
not critical but behavior under varying input/output voltage and load
conditions will be affected by C2 and C3, the number of turns on each of
the windings of T1, and the gain of your particular transistors. However,
See note (3) about starting.

7. WARNING: Output is high voltage and dangerous - even more so if you increase
its output for true HV applications. Over 200 W is available continuously.
Take appropriate precautions.

8.
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |

--------------------------------------------------------------------------------

Chapter 9) Kevin's Strobe Schematics

--------------------------------------------------------------------------------

9.1) High power inverter and trigger circuits

(From: Kevin Horton (khorton@tech.iupui.edu)).

I'm building a super strobe bar! It has 8 strobe tubes under computer
control. (Actually a PIC processor, but hey, computer is a computer.)
I have all the stuff done except the control section, and I only have
2 of the 8 strobe units done due to the fact that I haven't found any
more cheap cameras at the thrift store! (One Saturday morning's worth of
garage sales and flea markets would remedy that! --- sam).

It runs on 12 V, at up to 6 A, and can fire the tubes at a rate of about 8-10
times per second. The storage cap is a 210 uf, 330 V model; it gets to about
250 V to 300 V before firing; depending on how long it has had to charge.
Because of this high speed, the tubes get shall we say, a little warm. (Well,
maybe a lot warm --- sam). I have it set up at the moment driving two
alternating 5 W-s tubes. I'm pumping them quite a bit too hard, as the
electrodes start to glow after oh, about 5 seconds or so of continuous use.
I know, a high class problem, indeed! My final assembly will have 8 tubes
spaced about 8 inches apart on a 2x4, with a Plexiglass U-shaped enclosure
with a nice 12 V fan blowing air through one end of the channel to cool the
inverter and the tubes. Stay tuned.

Inverter - High power 12 V to 300 V inverter for high repeat rate medium
power strobes. Schematic in GIF format: inverter.gif

Trigger - Opto-isolated logic level trigger for general strobe applications.
Schematic in GIF format: trigger.gif

--------------------------------------------------------------------------------

9.2) Tiny tiny inverter design

I have developed a cool little transformer circuit that seems to be
very efficient. I built this inverter as tiny as I could make it.
It runs off of 3V, and charges up a little 1 uf 250V cap all the way up in
about 30 seconds; drawing about 5 to 8 mA in the process. The numbers by the
windings tell the number of turns. The primary and feedback windings are
#28, while the secondary is #46. Yes, #46! I could hardly tell what
gauge it was, as it was almost too small to measure with my micrometer!
It may be #44 or #45, but at these sizes, who knows? I used a trigger
transformer for the wire. I used all the wire on it, to be exact; it
all JUST fit on the little bobbin. The primary went on the core first,
then the secondary, and finally the feedback winding. This order is
very important. I used a ferrite bobbin and corresponding ferrite 'ring'
that fit on it. The whole shebang was less than 1 cm in diameter, and
about 3-5 mm high! I gave it a coat of wax to seal things up, and made
the inverter circuit with surface-mount parts, which I then waxed onto the
top. There are two wires in, and two wires out. It's enough to run a
neon fairly brightly at 1.2 V, with a 3 ma current draw.

Schematic in GIF format: teeny.gif

Vcc >---+--------------+ T1
| 6T )||
\ #28 )|| +-------o HV output
R1 / )||(
47K \ +---+ ||(
/ 2N4401 | ||(
| |/ C ||( 450T
| +--| Q1 ||( #46
| | |\ E ||(
| | | ||(
+--+ +--------+ ||(
| | |17T )||(
C1 _|_ | |#28 )|| +-------o HV return
.001 uF --- | | )||
| +-----------+
| |
Gnd >----+----------+

--------------------------------------------------------------------------------

Chapter 10) IR Detector/Tester Circuits

Two approaches are shown below.

* The first uses a bare photodiode as the sensor. It is simpler, lower power,
and shouldn't care what, if any, modulation is used by the IR source.

* An IR detector module salvaged from a TV or VCR, or purchased from Radio
Shack or elsewhere may be used instead of a photodiode. This will have a
much greater dynamic range (response to both weak and powerful signals)
than a simple photodiode. However, some of these assume a particular
modulation frequency and will be blind to anything else. Power requirements
may also be more restrictive - it may insist on regulated 12 V).

--------------------------------------------------------------------------------

10.1) IR detector circuit using bare photodiode

This IR Detector may be used for testing of IR remote controls, CD player
laser diodes, and other low level near IR emitters. It will not have the
sensitivity or dynamic range of the approach described in the section: "IR detector circuit using IR receiver module" but will respond to all sources
of IR falling within the wavelength range of the photodiode used since there
is not demodulation or coupling circuitry to get in the way.

IR radiation falling on the photodiode causes current to flow through R1
to the base of Q1 switching it and LED1 on.

Component values are not critical. Purchase photodiode sensitive to near
IR - 750-900 um or salvage from optocoupler or photosensor. Dead computer
mice, not the furry kind, usually contain IR sensitive photodiodes. For
convenience, use a 9V battery for power. Even a weak one will work fine.
Construct the circuit so that the LED does not illuminate the photodiode!

The detected signal may be monitored across the transistor with an
oscilloscope.

Vcc (+9 V) o-------+---------+
| |
| \
/ / R3
\ R1 \ 500
/ 3.3K /
\ __|__
| _\_/_ LED1 Visible LED
__|__ |
IR ----> _/_\_ PD1 +--------o Scope monitor point
Sensor | | (low active)
Photodiode | B |/ C
+-------| Q1 2N3904
| |\ E
\ |
/ R2 +--------o Gnd
\ 27K |
/ |
| |
Gnd o--------+---------+
_|_
-

--------------------------------------------------------------------------------

10.2) IR detector circuit using IR receiver module

This one uses an entire IR receiver module as the IR sensor. Its sensitivity
and dynamic range will be much better than the circuit described in the
section: "IR detector circuit using bare photodiode" since these modules
have automatic gain control circuitry built in. However, some modules are
tuned to a particular modulation frequency and/or are AC coupled and will not
respond to all remotes or other pulsed or continuous IR sources.

The IR receiver module from a TV, VCR, or purchased from Radio Shack or
elsewhere, drives the base of Q1 through R1. It may even be possible to
eliminate the transistor circuit entirely and connect the LED directly to the
module's output (in series with a current limiting resistor to Vcc or Gnd) but
that depends on the drive capabilities of the module. You can use whatever
Vcc is required for the IR receiver module for the LED circuit as well but may
need to change the value of R2 to limit the current to the LED to less than
its maximum rating.

The specific case where Vcc is +5 V is shown.

R2
Vcc (+5) o------+-----------/\/\--------+
| 220 __|__
| _\_/_ LED1 Visible LED
| |
|+ +--------o Scope monitor point
+----------+ | (low active)
-| IR |out R1 B |/ C
IR ---> : Receiver |------/\/\-----| Q1 2N3904
-| Module | 10K |\ E
+----------+ |
|- |
Gnd o------+-----------------------+--------o Gnd
_|_
-

--------------------------------------------------------------------------------

Chapter 11) Basic Incandescent Light Dimmer Circuits

These are the type of common light dimmers (e.g., replacements for standard
wall switches) widely available at hardware stores and home centers.

CAUTION: However, note that a dimmer should not be wired to control an
outlet since it would be possible to plug a device into the outlet which
might be incompatible with the dimmer resulting in a safety or fire hazard.

While designed for incandescent or heating loads only, these will generally
work to some extent with universal motors as well as fluorescent lamps down
to about 30 to 50 percent brightness. Long term reliability is unknown for
these non-supported applications.

--------------------------------------------------------------------------------

11.1) Simplest dimmer schematic

The first schematic is of a normal (2-way) inexpensive dimmer - in fact this
contains just about the minimal number of components to work at all!

S1 is part of the control assembly which includes R1.

The rheostat, R1, varies the amount of resistance in the RC trigger circuit.
The enables the firing angle of the triac to be adjusted throughout nearly
the entire length of each half cycle of the power line AC waveform. When
fired early in the cycle, the light is bright; when fired late in the cycle,
the light is dimmed. Due to some unavoidable (at least for these cheap
dimmers) interaction between the load and the line, there is some hysteresis
with respect to the dimmest setting: It will be necessary to turn up the
control a little beyond the point where it turns fully off to get the light
to come back on again.

Black o--------------------------------+--------+
| |
| | |
R1 \ | |
185 K /<-+ |
\ v CW |
| __|__ TH1
| _\/\_ Q2008LT
+---|>| / | 600 V
| |<|--' |
C1 _|_ Diac |
.1 uF --- (part of |
S1 | TH1) |
Black o------/ ---------------------+-----------+

--------------------------------------------------------------------------------

11.2) 3-way dimmer schematics

There are at least two varieties of inexpensive 3-way style dimmer switches
which differ mainly in the switch configuration, not the dimmer circuitry.
You will probably have no reliable way of telling them apart without testing
or disassembly.

None of the simple 3-way dimmer controls permit totally independent dimming
from multiple locations. With some, a dimmer can be installed at only one
switch location. Fully electronic approaches (e.g., 'X10') using master
programmers and addressable slave modules can be used to control the intensity
of light fixtures or switch appliances on or off from anywhere in the house.

However, for one simple, if inelegant, approach to independent dimming, see
the section: "Independent dimming from two locations - kludge #3251".

--------------------------------------------------------------------------------

11.3) Simple 3-way dimmer schematic 1

The schematic below is of one that is essentially a normal 3-way switch with
the dimmer in series with the common wire. Only one of these should be
installed in a 3-way circuit. The other switch should be a normal 3-way
type. Otherwise, the setting of the dimmer at one location will always
affect the behavior of the other one (only when the remote dimmer is at its
highest setting - full on - will the local dimmer have a full range and
vice-versa).

Note that the primary difference between this 3-way dimmer schematic and
the normal dimmer schematic shown above is the addition of an SPDT switch -
which is exactly what is in a regular 3-way wall switch. However, this
dimmer also includes a choke (L1) and capacitor (C2) to suppress Radio
Frequency Interference (RFI). Operation is otherwise identical to that
of the simpler circuit.

This type of 3-way dimmer can be used at only one end of a multiple switch
circuit. All the other switches should be conventional 3-way or 4-way types.
Thus, control of brightness is possible only from one location.

Red 1 o--------o
\
S1 o----+------------+-----------+
| | |
Red 2 o--------o | R1 \ ^ CW |
| 220 K /<-+ |
| \ | |
| | | |
| +--+ |
| | |
| R2 / |
C2 _|_ 47 K \ |
.047 uF --- / __|__ TH1
| | _\/\_ SC141B
| +---|>| / | 200 V
| | |<|--' |
| C1 _|_ D1 |
| .062 uF --- Diac |
| | |
Black o-----------------+---CCCCCC---+-----------+
L1
40 T #18, 2 layers
1/4" x 1" ferrite core

--------------------------------------------------------------------------------

11.4) Simple 3-way dimmer schematic 2

The schematic below is of a 3-way dimmer with a slightly more complex
switching arrangement such that when the local dimmer is set to full on or
full off, it is bypassed. (If you ignore the intermediate dimming range of
the control, it behaves just like a normal 3-way switch.) With this scheme,
it is possible to have dimmers at both locations without the dimmer
circuitry ever being in series and resulting in peculiar behavior.

Whether this is really useful or not is another story. The wiring would be
as follows:

Location 1 Location 2
3-way Dimmer A 3-way Dimmer +---------+
/o----------------------o\ | Lamp |
Hot o------o/ Silver 1 Silver 2 \o------| or |-----o Neutral
Brass o----------------------o Brass | Fixture |
Silver 2 B Silver 1 +---------+

(If dimming interacts, interchange the A and B wires to the silver screws at
one dimmer).

This one uses a toggle style potentiometer where the up and down positions
operate the switches. Therefore, it has 3 states: Brass to Silver 1 (fully
up), dim between Brass and Silver 1 (intermediate positions), and Brass to
Silver 2 (fully down).

Br /o---o Br o---o Br/\/o---o
3-way dimmer is up o---o/ S1 or down o---o\ S1 or Dim o---o S1
o---o \o---o o---o
S2 S2 S2

However, it is still not possible to have totally independent control - local
behavior differs based on the setting of the remote dimmer (details left as
an exercise for the reader).

Like the previous circuit, this dimmer also includes a choke (L1) and
capacitor (C3) to suppress Radio Frequency Interference (RFI). It is just
a coincidence (or a matter of cost) that the 3-way dimmers have RFI filters
and the 2-way type shown above does not.

Silver 1 o---+----------------+--------------------+-----------+
| | | |
| | R1 \ ^ Up |
| | 150 K /<-+ |
| | \ | |
| | | | |
| | +---------+--+ |
| | | | |
| C3 _|_ | R2 / |
| --- | 22 K \ |
| | | / __|__ TH1
| | C2 _|_ | _\/\_
| | .047 uF --- +---|>| / | 200 V
Up \ | | | |<|--' |
| | | C1 _|_ D1 |
| | |.047 uF --- Diac |
| | | | |
| Dim o--------+---CCCC---+---------+-----------+
| / L1
Brass o---+---o 12T #18
1/4" x 1/2" ferrite core
Down o
|
Silver 2 o-----------+

--------------------------------------------------------------------------------

11.5) Independent dimming from two locations - kludge #3251

Here is a scheme which will permit dimming with independent control from two
locations. Each location will have a normal switch and a dimmer knob. The
toggle essentially selects local or remote but like normal 3-way switches, the
actual position depends on the corresponding setting of the other switch:

Location 1 Location 2
+--------+ 4-way SW 3-way SW
Hot o--+---| Dimmer |----o\ /o--------o\ +---------+
| +--------+ / \o----------| Fixture |------o Neutral
| +--o/ \o--------o Center +---------+ Shell
| | (brass) (silver)
| | +--------+
| +------------| Dimmer |--+
| +--------+ |
+---------------------------------------+

As usual, the brass screw on the fixture or outlet should be connected to the
Hot side of the wiring and the silver screw to the Neutral side.

The dimmers can be any normal knob or slide type with an off position.

Note that as drawn, you need 4 wires between switch/dimmer locations.
4-way switches are basically interchange devices - the connections
are either an X as shown or straight across. While not as common as
3-way switches, they are available in your favorite decorator colors.

If using Romex type cable in between the two locations, make sure to tape or
paint the ends of the white wires black to indicate that they may be Hot as
required by Code.

And, yes, such a scheme will meet Code if constructed using proper wiring
techniques.

No, I will not extend this to more than 2 locations!

--------------------------------------------------------------------------------

Chapter 12) Simple Power Supplies

This is a (currently somewhat meager) collection of basic power supply
circuits that will hopefully grow as time passes.

--------------------------------------------------------------------------------

12.1) Converting an AC output wall adapter to DC

Where a modest source of DC is required for an appliance or other device,
it may be possible to add a rectifier and filter capacitor (and possibly
a regulator as well) to a wall adapter with an AC output. While many wall
adapter output DC, some - modems and some phone answering machines, for
example - are just transformers and output low voltage AC.

This is also the simplest and safest way to construct a small DC power supply
as you do not need to deal with the 110 VAC at all.

To convert such an adapter to DC requires the use of:

* Bridge rectifier - turns AC into pulsating DC.
* Filter capacitor - smooths the output reducing its ripple.
* Regulator - produces a nearly constant output voltage.

Depending on your needs, you may find a suitable wall adapter in your junk
box (maybe from that 2400 baud modem that was all the rage a couple of years
ago!).

The basic circuit is shown below:

Bridge Rectifier Filter Capacitor

AC o-----+----|>|-------+---------+-----o DC (+)
~| |+ |
In from +----|<|----+ | +_|_ Out to powered device
AC wall | | C ___ or voltage regulator
Adapter +----|>|----|--+ - |
| | |
AC o-----+----|<|----+------------+-----o DC (-)
~ -

Considerations:

* An AC input of Vin VRMS will result in a peak output of approximately
1.4 Vin - 1.4 V. The first factor of 1.4 results from the fact that the
peak value of a sinusoid (the power line waveform) is 1.414 (sqrt(2))
times the RMS value. The second factor of 1.4 is due to the two diodes
that are in series as part of the bridge rectifier. The fact that they
are both about 1.4 is a total coincidence.

Therefore, you will need to find an AC wall adapter that produces an output
voltage which will result in something close to what you need. However,
this may be a bit more difficult than it sounds since the nameplate rating
of many wall adapters is not an accurate indication of what they actually
produce especially when lightly loaded. Measuring the output is best.

* Select the filter capacitor to be at least 10,000 uF per 1000 mA of output
current with a voltage rating of at least 2 x Vin. This rule of thumb will
result in a ripple of less than 1 V p-p which will be acceptable for many
devices or where a voltage regulator is used (but may be inadequate for
some audio devices resulting in some 120 Hz hum. Use a larger or additional
capacitor or a regulator in such a case.

* Suitable components can be purchased at any electronics distributor as well
as Radio Shack. The bridge rectifier comes as a single unit or you can put
one together from 1N400x diodes (the x can be anything from 1 to 7 for these
low voltage applications). Observe the polarity for the filter capacitor!

The following examples illustrate some of the possibilities.

* Example 1: A typical modem power pack is rated at 12 VAC but actually
produces around 14 VAC at modest load (say half the nameplate current
rating). This will result in about 17 to 18 VDC at the output of the
rectifier and filter capacitor.

* Example 2: A cordless VAC battery charger adapter might produce 6 VAC.
This would result in 6 to 7 VDC at the output of the rectifier and filter
capacitor.

Adding an IC regulator to either of these would permit an output of up to
about 2.5 V less than the filtered DC voltage.

--------------------------------------------------------------------------------

12.2) Adding an IC regulator to a wall adapter or battery

For many applications, it is desirable to have a well regulated source of
DC power. This may be the case when running equipment from batteries as
well as from a wall adapter that outputs a DC voltage or the enhanced adapter
described in the section: "Converting an AC output wall adapter to DC".

The following is a very basic introduction to the construction of a circuit
with appropriate modifications will work for outputs in the range of about
1.25 to 35 V and currents up 1 A. This can also be used as the basis for a
small general purpose power supply for use with electronics experiments.

What you want is an IC called an 'adjustable voltage regulator'. LM317 is one
example - Radio Shack should have it along with a schematic. The LM317 looks
like a power transistor but is a complete regulator on a chip.

Here is a sample circuit:

I +-------+ O
Vin (+) o-----+---| LM317 |---+--------------+-----o Vout (+)
| +-------+ | |
| | A / |
| | \ R1 = 240 |
| | / | ___
_|_ C1 | | +_|_ C2 |_0_| LM317
--- .01 +-------+ --- 1 uF | | 1 - Adjust
| uF | - | |___| 2 - Output
| \ | ||| 3 - Input
| / R2 | 123
| \ |
| | |
Vin(-) o------+-------+----------------------+-----o Vout (-)

Note: Not all voltage regulator ICs use this pinout. If you are not using an
LM317, double check its pinout - as well as all the other specifications.

For the LM317:

1. R2 = (192 x Vout) - 240, where R2 in ohms, Vout is in volts and must be at
between 1.2 V and 35 V.

2. Vin should be at least 2.5V greater than Vout. Select a wall adapter with
a voltage at least 2.5 V greater than your regulated output at full load.

However, note that a typical adapter's voltage may vary quite a bit
depending on manufacturer and load. You will have to select one that
isn't too much greater than what you really want since this will add
unnecessary wasted power in the device and additional heat dissipation.

3. Maximum output current is 1 A. Your adapter must be capable of supplying
the maximum current safely and without its voltage drooping below the
requirement in (2) above.

4. Additional filter capacitance (across C1) on the adapter's output may help
(or be required) to reduce its ripple and thus the swing of its input.
This may allow you to use an adapter with a lower output voltage and reduce
the power dissipation in the regulator as well.

Using 10,000 uF per *amp* of output current will result in less than 1 V
p-p ripple on the input to the regulator. As long as the input is always
greater than your desired output voltage plus 2.5 V, the regulator will
totally remove this ripple resulting in a constant DC output independent
of line voltage and load current fluctuations. (For you purists, the
regulator isn't quite perfect but is good enough for most applications.)

Make sure you select a capacitor with a voltage rating at least 25% greater
than the adapter's *unloaded* peak output voltage and observe the polarity!

Note: wall adapters designed as battery chargers may not have any filter
capacitors so this will definitely be needed with this type. Quick check:
If the voltage on the adapter's output drops to zero as soon as it is pulled
from the wall - even with no load - it does not have a filter capacitor.

5. The tab of the LM317 is connected to the center pin - keep this in mind
because the chip will have to be on a heat sink if it will be dissipating
more than a watt or so. P = (Vout - Vin) * Iout.

6. There are other considerations - check the datasheet for the LM317
particularly if you are running near the limits of 35 V and/or 1 A.

--------------------------------------------------------------------------------

Chapter 13) Discrete Multivibrator Schematic

This is an astable multivibrator using discrete parts. Yes, I know, low tech
but you can actually fondle all the internal points of interest that way :-).

The time constant of R1*C1 and R2*C2 determine the blink rate. (Try 50K, 10
uF to start for a visible blink rate).

You can also put an LED in series with one or both of the collector resistors
(to blink alternately) and do away with any additional buffers.

Modify the values of these pair of Rs and Cs for operation at higher or lower
frequencies. Some considerations:

* For very low Cs, stray capacitance and device frequency response will limit
highest frequency.

* For very large Cs and/or very large Rs, leakage will limit lowest frequency.

* For very large Rs, gain of transistors may be inadquate.

* For very small Rs, transistors may melt down :-).

Note: C1 and C2 can be either non-polarized or polarized (electrolytic) types.
If polarized (e.g., to obtain higher capacitance values for lower operating
frequencies), install the capacitors in the direction shown.

Vcc
o
|
+----+-------+--------+----+--------------+
| | | | |
| | | | /
/ / / / \ 220
\ 1K \ R1 \ R2 \ 1K /
/ / / / \
\ \ \ \ __|__
| | | | _\_/_ LED
+--------------+ | | |
| | +--|-----------+ | Q1-Q3: 2N3904 or similar
| | | | | | 10K |/ C general purpose
| | | | | +----/\/\----| Q3 NPN transistor.
C \| | C1 | | C2 | |/ C |\ E
Q1 |--+--)|--+ +--|(--+--| Q2 |
E /| - + + - |\ E _|_
_|_ _|_ -
- -

Question for the student: What happens if one or both Cs are replaced by
resistors?

--------------------------------------------------------------------------------

Chapter 14) Ultrasonic cleaner schematic

Ultrasonic cleaning is a means of removing dirt and surface contamination from
intricate and/or delicate parts using powerful high frequency sound waves in
a liquid (water/detergent/solvent) bath.

An ultrasonic cleaner contains a power oscillator driving a large piezoelectric
transducer under the cleaning tank. Depending on capacity, these can be quite
massive.

A typical circuit is shown below. This is from a Branson Model 41-4000 which
is typical of a small consumer grade unit.

R1 D1
H o------/\/\-------|>|----------+
1, 1/2 W EDA456 |
C1 D2 |
+----||----+----|>|-----+
| .1 uF | EDA456 | 2
| 200 V | +-----+---+ T1 +---+------->>------+
| R2 | _|_ C2 )|| o 4 | | |
+---/\/\---+ --- .8 uF D )|| +----+ | |
| 22K _|_ 200 V )||( + |
| 1 W - 1 o )||( )|| _|_
+-----------------+---------+ ||( O )|| L1 _x_ PT1
| R3 | 7 ||( )|| |
| +---/\/\---+ +-----+ ||( 5 + |
C \| | 10K, 1 W | F )|| +---+ | |
Q1 |--+-+--------------+ 6 o )|| | | |
E /| | D3 R4 +---+ +----+------->>------+
| +--|<|---/\/\--+ _|_
| 47, 1 W | --- Input: 115 VAC, 50/60 Hz
| | | Output: 460 VAC, pulsed 80 KHz
N o------+-------------------+---+

The power transistor (Q1) and its associated components form an self excited
driver for the piezo-transducer (PT1). I do not have specs on Q1 but based on
the circuit, it probably has a Vceo rating of at least 500 V and power rating
of at least 50 W.

Two windings on the transformer (T1, which is wound on a toroidal ferrite
core) provide drive (D) and feedback (F) respectively. L1 along with the
inherent capacitance of PT1 tunes the output circuit for maximum amplitude.

The output of this (and similar units) are bursts of high frequency (10s to
100s of KHz) acoustic waves at a 60 Hz repetition rate. The characteristic
sound these ultrasonic cleaners make during operation is due to the effects
of the bursts occuring at 60 Hz since you cannot actually hear the ultrasonic
frequencies they use.

The frequency of the ultrasound is approximately 80 KHz for this unit with a
maximum amplitude of about 460 VAC RMS (1,300 V p-p) for a 115 VAC input.

WARNING: Do not run the device with an empty tank since it expects to have
a proper load. Do not touch the bottom of the tank and avoid putting your
paws into the cleaning solution while the power is on. I don't know what,
if any, long term effects there may be but it isn't worth taking chances.
The effects definitely feel strange.

Where the device doesn't oscillate (it appears as dead as a door-nail), first
check for obvious failures such as bad connections and cracked, scorched, or
obliterated parts.

To get inside probably requires removing the bottom cover (after pulling the
plug and disposing of the cleaning solution!).

CAUTION: Confirm that all large capacitors are discharged before touching
anything inside!

The semiconductors (Q1, D1, D2, D3) can be tested for shorts with a multimeter
(see the document: "Basic Testing of Semiconductor Devices".

The transformer (T1) or inductor (L1) could have internal short circuits
preventing proper operation and/or blowing other parts due to excessive load
but this isn't kind of failure likely as you might think. However, where all
the other parts test good but the cleaning action appears weak without any
overheating, a L1 could be defective (open or other bad connections) detuning
the output circuit.

--------------------------------------------------------------------------------

Chapter 15) Range, oven, and furnace electronic ignition Schematic

Many modern gas stoves, ovens, furnaces, and other similar appliances use an
electronic ignition rather than a continuously burning pilot flame to ignite
the fuel. These are actually simple high voltage pulse generators.

* Where starting is manual (there is a 'start' position on the control(s), a
set of switch contacts on the control(s) provides power to the ignition
module.

- A problem of no spark with only one control indicates that the fault is
with it or its wiring.

- A problem with continuous sparking even with all the controls off or in
their normal positions indicates a short - either due to a defective switch
in one of the controls or contamination bypassing the switch contacts.

* Where starting is automatic, an electronic sensor, thermocouple, or bimetal
switch provides power to the ignition module as needed.

The Harper-Wyman Model 6520 Kool Lite(tm) module is typical of those found in
Jenne-Aire and similar cook-tops. Input is 115 VAC, 4 mA, 50/60 Hz AC. C1
and D1 form a half wave doubler resulting in 60 Hz pulses with a peak of about
300 V and at point A and charges C2 to about 300 V through D2. R2, C3, and
DL1 form a relaxation oscillator triggering SCR1 to dump the charge built up
on C2 into T1 with a repetition rate of about 2 Hz.

C1 A D1 T1 o
H o----||----------------+-------|>|-------+-------+ +-----o HVP+
.1 uF D2 1N4007 | 1N4007 | | o ||(
250 V +----|>|----+ | +--+ ||(
| | | )||(
+---/\/\----+ | #20 )||( 1:35
| R1 1M | C2 _|_ )||(
| R2 / 1 uF --- +--+ ||(
| 18M \ DL1 400 V | __|__ ||(
| / NE-2 | _\_/_ +-----o HVP-
| | +--+ | / |
| +----|oo|----+---------' | SCR1
| C3 | +--+ | | | S316A
| .047 uF _|_ R3 / | | 400 V
| 250 V --- 180 \ | | 1 A
| | / | |
R4 2.7K | | | | |
N o---/\/\---+-----------+------------+----+-------+

--------------------------------------------------------------------------------

Chapter 16) Bug Zapper

You know the type - a purplish light with an occasional (or constant) Zap!
Zap! Zap! If you listen real closely, you may be able to hear the screams of
the unfortunate insects as well :-).

The high-tech versions consist of a high voltage low current power supply and
fluorescent (usually) lamp selected to attract undesirable flying creatures.
(Boring low-tech devices may just use a fan to direct the insects to a tray of
water from which they are too stupid to be able to excape!)

However, these devices are not selective and will obliterate friendly and
useful bugs as well as unwanted pests.

Here is a typical circuit:

S1 R1 C1 C2 C1-C4: .5 uF, 400 V
H o----o/ o--+--/\/\--------||---+--------||---------+ D1-D5: 1N4007
| 25K D1 | D2 D3 | D4
| +---|>|---+---|>|---+---|>|---+---|>|---+
+-+ | C3 | C4 |
AC Line |o| FL1 +---+----||----+----+---+----)|----+----+--o +
+-+ Lamp | | R3 | | R4 | 500 to
| | +---/\/\---+ +---/\/\---+ 600 V
| R2 | 10M 10M to grid
N o----------+--/\/\---+------------------------------------------o -
25K

This is just a line powered voltage quadrupler. R1 and R2 provide current
limiting when the strike occurs (and should someone come in contact with the
grid). The lamp, FL1, includes the fluorescent bulb, ballast, and starter (if
required). Devices designed for jumbo size bugs (or small rodents) may use
slightly larger capacitors!

--------------------------------------------------------------------------------

Chapter 17) Electronic Air Cleaner HV Generator

At least I assume this cute little circuit board is for an electronic air
cleaner or something similar (dust precipitator, positive/negative ion
generator, etc.)! I received the unit (no markings) by mistake in the mail.
However, I did check to make sure it wasn't a bomb before applying power. :-)

This module produces both positive and negative outputs when connected to 115
VAC, 60 Hz line voltage. Each is about 5 KV at up to around 5 uA.

D1 T1 o
H o--------------|>|----+---+--------------------+ +-----o A
1N4007 | | Sidac __|__ SCR1 |:|(
| | R3 D2 100 V _\_/_ T106B2 |:|(
AC C1 | +--/\/\---|>| / | 200 V |:|(
Line Power .15 uF _|_ 1.5K |<|--+--' | 4 A o |:|( 350 ohms
IL1 LED 250V --- _|_ | +-------+ |:|(
+--|<|---+ | C2 --- | | )|:|(
| R1 | R2 | .0047 uF | | | .1 ohm )|:|(
N o---+--/\/\--+--/\/\--+ +-----+--+ )|:|(
470 3.9K | +--+ +--+--o B
1 W 2 W | | R4 |
+--------------------------------+---/\/\----+
2.2M

The AC input is rectified by D1 and as it builds up past the threshold of the
sidac (D2, 100 V), SCR1 is triggered dumping a small energy storage capacitor
(C1) through the primary of the HV transformer, T1. This generates a HV pulse
in the secondary. In about .5 ms, the current drops low enough such that the
SCR turns off. As long as the instantaneous input voltage remains above about
100 V, this sequence of events repeats producing a burst of 5 or 6 discharges
per cycle of the 60 Hz AC input separated by approximately 13 ms of dead time.

The LED (IL1) is a power-on indicator. :-)

The transformer was totally potted so I could not easily determine anything
about its construction other than its winding resistances and turns ratio
(about 1:100).

A o
C3 |
+------||-------+
R5 R6 D3 | D4 D5 | D6 R7 R8
HV- o--/\/\---/\/\--+--|>|--+--|>|--+--|>|--+--|>|---/\/\--+--/\/\--o HV+
10M 10M | C4 | 220K | 10M
+------||-------+ |
D3-D6: 10 KV, 5 mA _|_ _|_
C3,C4: 200 pF, 10 KV --- C5 --- C6
C5,C6: 200 pF, 5 KV | |
B o--+----------------------+

The secondary side consists of a voltage tripler for the negative output
(HV-) and a simple rectifier for the positive output (HV+). This asymmetry is
due to the nature of the unidirectional drive to the transformer primary.

From my measurements, this circuit produces a total of around 10 KV between
HV+ and HV-, at up to 5 uA. The output voltages are roughly equal plus and
minus when referenced to point B.

I assume the module would also operate on DC (say, 110 to 150 V) with the
discharges repeating continuously at about 2 KHz. Output current capability
would be about 5 times greater but at the same maximum (no load) voltage.
(However, with DC, if the SCR ever got stuck in an 'on' state, it would be
stuck there since there would be no AC zero crossings to force it off. This
wouldn't be good!)

The secondary side circuitry can be easily modified or redesigned to provide
a single positive or negative output or for higher or lower total voltage.
Simply removing R4 will isolate it from the input and earth ground (assuming
T1's insulation is adequate).

Where there is no high voltage from such a device, check the following:

* Make sure power is actually getting to the high voltage portion of the unit.
Test the wall socket and/or AC adapter or other power supply for proper
voltage with a multimeter.

* Excessive dirt/dust/muck/moisture or physical damage or a misplaced paper
clip may be shorting it out or resulting in arcing or corona (a strong aroma
of ozone would be an indication of this). With such a small available
current (only uA) it doesn't take much for contamination to be a problem.
Thoroughly clean and dry the unit and check for shorts (with a multimeter
between the HV electrodes and case) and then test it again. Your problems
may be gone!

* If this doesn't help and the unit is not fully potted (in which case,
replacement is the only option), check for shorted or open components,
especially the power semiconductors.

--------------------------------------------------------------------------------

Chapter 18) Auto Air Purifier HV Generator

Well, maybe :-). This thing is about the size of a hot-dog and plugs
into the cigarette lighter socket. It produces a bit of ozone and who knows
what else. Whether there is any effect on air quality (beneficial or
otherwise) or any other effects is questionable but it does contain a nice
little high voltage circuit.

DL1 +-+ |
o T1 +-------+-----|o|
+12 o---+--------+----------+---------------------+ ||( | +-+ |
| | | D 30T )||( | DL2 +-+
| | -_|_ 4.7uF #30 )||( +-----|o| |
| | --- 50V +------+ ||( 3000T | +-+
| _|_ C2 + | | ||( #44 | DL3 +-+ |
| --- 470pF +--------------|------+ ||( +-----|o|
| | | | F 30T )||( | +-+ |
+_|_ C1 | | D1 | #36 )||( | DL4 +-+
--- 33uF +----------|---+---|<|----|------+ ||( +-----|o| |
- | 16V | | | 1N4002 | o +--+ +-+
| / / | |/ C o | |
| R1 \ R2 \ +--------|Q1 TIP41 +--------------+
| 1K / 4.7K / |\ E | Grid
| \ \ | |
| | | | |
GND o---+--------+----------+--------------+--------------+

T1 is constructed on a 1/4" diameter ferrite core. The D (Drive) and F
(Feedback) windings are wound bifilar style (interleaved) directly on the
core. The O (Output) winding is wound on a nylon sleeve which slips over
the core and is split into 10 sections with an equal number of turns (100
each) with insulation in between them.

DL1 to DL4 look like neon light bulbs with a single electrode. They glow like
neon light bulbs when the circuit is powered and seem to capacitively couple
the HV pulses to the grounded grid in such a way to generate ozone. I don't
know if they are filled with special gas or are just weird neon light bulbs.

--------------------------------------------------------------------------------

Chapter 19) Typical Rechargeable Flashlight Schematics

Here are circuit diagrams from several inexpensive rechargeable flashlights.
These all use very 'low-tech' chargers so battery life may not be as long as
possible and energy is used at all times when plugged into an AC outlet.

--------------------------------------------------------------------------------

19.1) First Alert Series 50 rechargeable flashlight schematic

This one is typical of combined all-in-one units using a lead-acid battery
that extends a pair of prongs to directly plug into the wall socket for
charging.

It is a really simple, basic charger. However, after first tracing out the
circuit, I figured only the engineers at First Alert knew what all the diodes
were for - or maybe not :-). But after some reflection and rearrangement of
diodes, it all makes much more sense: C1 limits the current from the AC line
to the bridge rectifier formed by D1 to D4. The diode string, D5 to D8 (in
conjunction with D9) form a poor-man's zener to limit voltage across BT1 to
just over 2 V.

The Series 50 uses a sealed lead-acid battery that looks like a multi-cell
pack but probably is just a funny shaped single cell since its terminal voltage
is only 2 V.

Another model from First Alert, the Series 15 uses a very similar charging
circuit with a Gates Cyclon sealed lead-acid single cell battery, 2 V, 2.5
A-h, about the size of a normal Alkaline D-cell.

WARNING: Like many of these inexpensive rechargeable devices with built-in
charging circuitry, there is NO line isolation. Therefore, all current
carrying parts of the circuit must be insulated from the user - don't go
opening up the case while it is plugged in!

2V LB1 Light
1.2A +--+ Bulb S1
+--------|/\|----------o/ o----+
_ F1 R3 D3 | +--+ |
AC o----- _----/\/\---+----|>|--+---|----------------------+ |
Thermal 15 | D2 | | 4A-h | |
Fuse | +--|>|--+ | BT1 - |+ 2V | |
| | D4 +--------------||------|-------+
+----|<|--+ | | | |
| D1 | | D8 D7 D6 D5 | D9 |
+--------+-------+--|<|--+---+--|<|--|<|--|<|--|<|--+--|>|--+
| | |
| / |
_|_ C1 \ R1 |
--- 2.2uf / 100K |
| 250V \ |
| | R2 L1 LED |
AC o---+--------+--------------/\/\-----------|<|------------------+
39K 1W Charging

--------------------------------------------------------------------------------

19.2) Black & Decker Spotlighter Type 2 rechargeable flashlight

This uses a 3 cell (3.6 V) NiCd pack (about 1 A-h). The charging circuit is
about as simple as it gets!

S1
11.2 VRMS +---------------o/ o----+
AC o-----+ T1 R1 LED1 D1 | +| | | - |
)|| +----/\/\-----|>|---->>----|>|----+---||||||---+ |
)||( 33 Charging 1N4002 | | | | KPR139 |
)||( 2W BT1 | LB1 |
)||( 3.6V, 1 A-h | +--+ |
)|| +-------------------->>------------------------+----|/\|--+
AC o-----+ Light Bulb +--+

|<------- Charger ---------->|<---------- Flashlight ----------->|

I could not open the transformer without dynamite but I made measurements of
open circuit voltage and short circuit current to determine the value of R1.
I assume that R1 is actually at least in part the effective series resistance
of the transformer itself.

Similar circuits are found in all sorts of inexpensive rechargeable devices.
These have no brains so they trickle charge continuously. Aside from wasting
energy, this may not be good for the longevity of some types of batteries (but
that is another can of worms).

--------------------------------------------------------------------------------

19.3) Brand Unknown (Made in China) rechargeable flashlight schematic

This is another flashlight that uses NiCd batteries. The charger is very
simple - a series capacitor to limit current followed by a bridge rectifier.

There is an added wrinkle which provides a blinking light option in addition
to the usual steady beam. This will also activate automatically should there
be a power failure while the unit is charging if the switch is in the 'blink'
position.

With Sa in the blink position, a simple transistor oscillator pulses the light
with the blink rate of about 1 Hz determined by C2 and R5. Current through R6
keeps the light off if the unit is plugged into a live outlet. (Q1 and Q2 are
equivalent to ECG159 and ECG123AP respectively.)

R1 D1 R3 LED1
AC o---/\/\----+----|>|-------+---+---/\/\--|>|--+ D1-D5: 1N4002
33 ~| D2 |+ | 150 |
1/2W +----|<|----+ | | R4 | D5
D3 | | +------/\/\----+--|>|--+
C1 +----|>|----|--+ | 33, 1/2W | LB1 2.4V
1.6uF ~| D4 | | | | | +--+ .5A
AC o--+---||---+----|<|----+--+---|--||||--------------+-+---|/\|----+
| 250V | |- | - | |+ | +--+ |
+--/\/\--+ | | BT1 + C2 - | R5 |
R2 | | 2.4V +---|(----|-----/\/\----+
330K | | | 22uF | 10K |
| | R6 | |/ E |
| +---/\/\---+-+-----| Q1 |
| 15K | |\ C +---------+
| / C327 | | |
| R7 \ PNP | | 1702N |
| 100K / | | NPN |/ C
| \ +---|-------| Q2
| On | | |\ E
| S1 o---------|-----------+ |
+----o->o Off | |
o---------+---------------------+
Blink/Power Fail

--------------------------------------------------------------------------------

Chapter 20) Interesting Sequential Neon Flasher

This is a sort of brain teaser since it certainly isn't intuitively obvious
how this circuit works (if it works at all). It may be instructive to start
with the degenerate case of 2 resistors, 2 neon lamps, and a single capacitor.
What happens with that configuration?

(From: Steve Roberts (osteven@akrobiz.com)).

+200V o----+-----+-----+-----+-----+
| | | | |
/ / / / /
\ R1 \ R2 \ R3 \ R4 \ R5 R1-R5: 2.7M
/ / / / /
\ \ \ \ \
| | | | |
+-o A +-o B +-o C +-o D +-o E
| | | | |
| IL1 | IL2 | IL3 | IL4 | IL5 IL1-IL5: NE2
+-+ +-+ +-+ +-+ +-+
|o| |o| |o| |o| |o|
+-+ +-+ +-+ +-+ +-+
| | | | |
Gnd o----+-----+-----+-----+-----+

Connect a .22 uF, 200 V capacitor between each of the following pairs of
points: A to C, A to D, B to D, B to E, C to E.

Neons will flash in sequence ABCDE if fed off DC. Momentarily removing the DC
will cause them to flash EDCBA.

From an ancient Radio Shack "Pbox" kit - the first kit I ever built!

INVERTER/UPS

2008-12-27T16:39:00.000-08:00

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At Powerworks we are very security minded, it’s our business. Not only do we manufacture and install a wide range of secure power systems such as UPS and Diesel Generators, we also custom design & build High Integrity Modular Computer Rooms, Data Centres and Comms Rooms to provide secure environments for all your vital IT equipment. All are installed by our NIC EIC approved electrical engineers and supervised by dedicated project managers.
Powerworks is the premiere provider of highly specialised UPS ‘Plus’ Solutions – technically superior redundant UPS and Generator systems which ensure reliability beyond ‘Tier 3’ or 99.99% uptime. Again designed by our technical team and installed to exceptionally high standards by our own engineers. Powerworks Service and Maintenance is recognised by our customers as being the best in the industry. We offer unrivalled levels of service at all times.
So whether it’s redundant power systems or a high integrity IT room that you require, Powerworks has a total solution designed to meet your organisation’s needs.
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“I have been very impressed by the installation quality, and the competence and friendliness of the staff. Powerworks was clearly the right choice of contractor for the supply of this very important service provision. Once again thank you.”
Geoff Copping at Fujitsu Siemens

Sinewave Power Inverters

2008-12-27T16:33:00.000-08:00

Sinewave Power Inverters
Sinewave inverters are most sophisticated power inverters on the market today. They are designed to precisely replicate and even improve on the quality of electricity supplied to your home / workplace. There is generally no incompatibilty with any appliance run from a Pure Sine wave inverter.We only sell Pure Sinewave Inverters Please select from the voltage range below to view available inverters.
12 Volt
24 Volt
48 Volt
108 Volt
<500va
<500va
<500va

500 - 1000VA
500 - 1000VA
500 - 1000VA

1000-2000VA
1000-2000VA
1000-2000VA
> 2000VA
> 2000VA
> 2000VA
> 2000VA

Solar Power Inverter The AJ series consist of pure sine wave inverters that convert the battery voltage to AC voltage for all AC appliances. The AJ series offer is a range from 275 to 2400VA (P30), high efficiency units with an outstanding overload capacity, thanks to the combined use of a toroidal transformer and a MOS power stage All the AJs in 12V and 24 V are certified according to the EC norm ECE-R 10 (E24).

12V Inverter, 12V DC Input to 120V AC Output NEW To thepowerstore.co.uk a range of High quality 12V 120V 60Hz AC output True Sinewave Inverters. 180VA to 3000VA Models available. Suitable for America.

12V Inverter, 12V DC Input to 230V AC Output Three ranges of high quality 12V True Sinewave Inverters from three of the worlds best inverter manufacturers. The NEW range of SK Inverters from Cotek with continuous power ratings between 200W and 3000W, Our NEW range of Phoenix Inverters from Victron Energy with continuous power ratings between 180W and 3000W+ when paralleled and our AJ, SI & HPSI Ranges from Studer Innotec with continuous power ratings between 200W and 2200W. Quality, Service, Support and Competitive Pricing.

24V Inverter, 24V DC Input to 120V AC Output NEW To thepowerstore.co.uk a range of High quality 24V 120V 60Hz AC output True Sinewave Inverters. 180VA to 3000VA Models available. Suitable for America.

24V Inverter, 24V DC Input to 230V AC Output Three ranges of high quality 24V True Sinewave Inverters from three of the worlds best inverter manufacturers. The NEW range of SK Inverters from Cotek with continuous power ratings between 200W and 3000W, Our NEW range of Phoenix Inverters from Victron Energy with continuous power ratings between 180W and 3000W+ when paralleled and our AJ, SI & HPSI Ranges from Studer Innotec with continuous power ratings between 300W and 4400W. Quality, Service, Support and Competitive Pricing.

48V Inverter, 48V DC Input to 230V AC Output Three ranges of high quality 48V True Sinewave Inverters from of the worlds best inverter manufacturers. The NEW range of SK Inverters from Cotek with continuous power ratings between 200W and 3000W, Our NEW range of Phoenix Inverters from Victron Energy with continuous power ratings between 220W and 3000W+ when paralleled and our AJ, SI & HPSI Ranges from Studer Innotec with continuous power ratings between 300W and 5000W. Quality, Service, Support and Competitive Pricing.

12V DC to 230V AC, 19 inch Rack Mount Inverters Two ranges of high quality 12V True Sinewave Inverters in 19" rack Mount Cabinets. The SI and HPSI Industrial Range from Studer are based on the SI Professional Inverters and have continuous power ratings between 600W and 3500W. The HPSI High Power Range have continuous power ratings between 2200W and 7000W.

24V DC to 230V AC, 19 inch Rack Mount Inverters Four model ranges of high quality 24V 600W to 24V 5000W True Sinewave Inverters in wall mount & 19" rack Mount Cabinets. The SI and HPSI Industrial Range from Studer and the PWS wall mount and rack mount from Convertronic.

48V & 60V DC to 230V AC, 19 inch Rack Mt Inverters Wide DC input range of inverters 42V-75VDC. The UNV inverter family represent latest DC to AC power conversion technology in 19" compatible mechanics. Suitable for any low to medium power UPS system these inverters are ideal for applications in telecommunica-tion, industrial, and railroad power supplies. These models also benefit from Parallel connection offering increased output power and / or (n+1) redundancy.

108V DC to 230V AC, 19 inch Rack Mount Inverter Wide DC input range of UNV inverters 77V-138VDC and the PWS inverters on 92V-135VDC. The UNV inverter family represent latest DC to AC power conversion technology in 19" compatible mechanics. Suitable for any low to medium power UPS system these inverters are ideal for applications in telecommunica-tion, industrial, and railroad power supplies. These models also benefit from Parallel connection offering increased output power and / or (n+1) redundancy. The PWS Range are available in Wall Mount or Rack Mount Variants.

216V DC to 230V AC, 19 inch Rack Mount Inverter The PWS inverter family is equipped with a low frequency isolation transformer following a primary side pulse width modulation stage and is available as 19” compatible rack or wall mounted cabinet. These inverters are especially suited for applications in power plant, industrial, rail, and shipping. AC power supplies up to 40kVA output power.

Inverter/Renewable Energy

2008-12-27T16:23:00.000-08:00

Enphase Raises US $15M for Micro-Inverters
California, United States [RenewableEnergyWorld.com]
Enphase Energy Inc. announced that it has raised US $15 million in new funding to expand manufacturing of its micro inverter systems. New investor RockPort Capital Partners led the round, and existing institutional investors Third Point Ventures and Applied Ventures LLC, the venture capital arm of Applied Materials Inc., also participated.
"The company's products are industry-defining and Enphase has proven management, a soaring market, and an excellent value proposition. We are committed to helping Enphase reach the next levels of success."-- Todd Wilson, General Partner, RockPort Capital Partners
“We are excited to join the Enphase team,” said Todd Wilson, general partner at RockPort Capital Partners, who will now join the Enphase Energy board of directors. “The company’s products are industry-defining and Enphase has proven management, a soaring market, and an excellent value proposition. We are committed to helping Enphase reach the next levels of success.”
The company had 1000 units of the product in Beta testing until June when they became commercially available. Since then the company said that it has received more than 1000 orders per month. The capital raised in this round will be used as working capital to help meet the level of demand and for Research & Development.
Enphase Energy micro-inverters are installed in commercial and residential solar power systems throughout the continental United States and Hawaii. Enphase products are compatible with most major brands of solar modules and are available from leading solar distributors and installers.
Enphase systems include micro-inverters that convert the DC power from each solar module to grid compliant AC power. In addition, the Enphase micro-inverters send performance information from each module to a secure website for analysis and visualization. Micro-inverters eliminate the need for a large centralized inverter. Enphase micro-inverter Systems have demonstrated energy harvest gains between 5 and 25% over traditional inverters, the company said.
For more on the micro-inverter technology, read our RE Insider Time for a Change: Micro-inverters Improve Performance of Solar Systems from Raghu Belur, co-founder and vice president of marketing at Enphase Energy.

Outstanding! My best wishes to the team at Enphase for an outstanding success and my complements to the backers who have real vision and a lion by the tail. This is exactly the type of technology the world needs now and I expect sales to be significant. So what's next - micro inverters for micro wind systems - mini micro inverters for micro energy recovery systems? There is just no limit for your technology. It reminds me of the laser. At first there were only a few clear applications. Now they are everywhere. I suspect that with continued research, innovation and very clever marketing, Enphase micro inverts can be too!Tom ConlonIron Man Windmill Co. LTD
Comment 1 of 4

A key value to smaller panel mounted inverters will be improved system life with respect to safety. Standards experts are finding that the major cause for failure of grid connected systems worldwide is caused through arc failures. Reducing DC cabling runs and junctions and reducing DC currents will result in safer systems.

I wrote a pretty long article about the pros vs. cons of microinverters here:http://www.solarpowerrocks.com/solar-trends/microinverters-my-turn-the-boring-technical-stuff/

I think micro inverters is a good solution for small grid tie aplications.Here in Mexico, most of the homes just need system below the 1kw, so enphase inverters is a good solution. it can reduce the cost of instalation and the cost of the system.Angel MejiaGEOPOWER

- Inverter Selection -

2008-12-27T16:18:00.000-08:00

Inverter Combis are increasingly getting more and more popular, and are ideal for most peoples needs on board their barges (and other boats), whether live aboard or leisure. They not only combine an inverter with battery charger but also include many other useful features, essential for comfortable cruising.
Whilst not an electronics expert, I have attempted to analyse product data and specifications of some of the more commonly available units, and give a few guidelines to features below. Please note they are only guidelines, obtained from manufacturers catalogues and web sites and as such are prone to changes and updates. If a certain function is important for your needs double check with the manufacturer that it is included before buying.

.http://www.victronenergy.com/DatasheetsPDF/SinusInverterChargers/GBPhoenixMulti.pdf
http://www.studer-inno.com/SITESTUDER/page/ANGLAIS/DescriptionE/HPCompactFichetechE.PDF
http://www.sterling-power.com/documents/bros04gb.pdf
http://www.mastervolt.com/dakarcombi/index.asp
http://www.powermastersystems.com/
Notes
May need powerman transfer switch when used together with generator
only one 230v AC input. Separate master switch required (£150) if shore and generator or both to be connected
New product, available soon
only one 230v AC input. Separate master switch required (£150) if shore and generator or both to be connected
Free technical & installation advice line - 01480 455060
Direct Mail order

Other similar versions available
7 other versions incl 24/300/70 and 12/1200/50 without power assist
3 other versions available incl 24v/2300w/55a and 24v/4000w/100a
.
6 other versions incl 12v,1500w,65a charger, 24/1800-35 and 24/3000-100
3 other versions (1500w and 24v) available

Manufacturers rated output
Care needs to be taken when buying an inverter as a 3000w inverter from one company could be less powerful than a 2000w inverter from another. This is because some manufactures base their rating on their maximum output, others at 30 minutes (P30) and others at continuous use at 40 deg C. Those that rate their outputs based on maximum power make them appear more powerful than they really are under normal operating conditions. For example, an inverter rated at 1500 watts (at 0 deg C) may only give 1000 watts if continuously rated at 20 deg C, or only 500 watts when rated continuously at 40 deg C.
The Victron 2500 watt combi is only 1600 watt at 40 deg C
The Mastervolt Dakar 2500 is only 2000 va (around 1600w) at 40 deg C
Sterling seem to be one of the few companies to rate their inverters at 40 deg C, so a 3000 watt Sterling inverter is 3000 watt at 40 deg C.
The problem in Europe is the absence of an agreed standard, unlike in North America where they have the A,B,Y,C. standards, which specify inverters (and battery chargers) at continuous use at 40 deg C ambient. If you want to compare inverter output power ratings then the best way is to compare the ABYC continuous use at 40 deg C rating, this way at least you will be comparing apples to apples, and 40 deg C is a more realistic temperature anywhere near the engine compartment than 20 deg C.
Wave Form
There are three inverter waveform types, square wave, quasi sine (or step square wave), and sine wave.
If you wish to run all appliance (especially washing machines, microwaves and timers) and you want to ensure there are no black lines on the TV, then you need to ensure you purchase a sine wave inverter. Quasi sine will run around 95% of most appliances and is very much cheaper with around 99% of all inverters sold being quasi sine. Most Combis have built in sine wave inverters, but check to make sure.
All inverters are attempting to mimic the mains 230 volt sine wave form. This ensures that all equipment to be run on an inverter receives the same input waveform for which it was designed. With some equipment such as heaters and lights the input waveform is not important. However with things like electric motors, and especially microwaves, the waveform is absolutely critical to achieve correct running.
The good side of a sine wave is it will run all equipment as well as the mains supply, however, the bad side is its cost and the fact that the quiescent current is about 2- times (and as much a 5 times) more than conventional quasi sine wave inverters
Automatic changeover - Uninterrupted A/C Power / Uninterrupted Crossover (UPS)
Most combis will automatically switch over to inverter power if shore power is disconnected, without loss of power. For example, the tv, pc etc. will remain switched on during transfer of power from shore power to inverter.
Built in power sharing / Power Control
Most combis have built in power sharing features, which will automatically reduce battery-charging power when other appliances are switched on, and have the ability to manually set maximum available incoming AC power. For example, if you are on an 8 amp shore power connection the incoming AC would be manually set to 8amps then if the battery charger is using 4 amps and a 1,400w (6amp) hair dryer is switched on the charging output is reduced to around 2 amps (35amps at 12v), giving full power to the hair dryer. When the hair dryer is switched off the battery charger will up it's power output to charge the batteries as fast as possible. Without this feature (or if separate charger and inverters installed) the 8amp shore power circuit breaker would trip as soon as the hair dryer is turned on. The Power Control function makes sure that only whatever current is “left over” is used to charge the batteries.
Power Assist
Some combis have the ability to combine their inverter output to that of the shore power and / or generator output. So that when a peak power is required for a limited period, the combi will make sure that insufficient shore or generator power is immediately compensated for by power from the battery. When the load reduces, the spare power is used to recharge the battery. For example if you have a limited shore power supply of 8 amps (1840watts) and a 2500 watt inverter you will be able to run appliances up to around 4340 watts, and even more for short periods at a time (because most 2500w inverters are capable of supplying more than 2500w for short periods, up to 6000w for a few seconds). Same with generator, for example a 4Kw generator plus 2500w inverter will give 6500w output.
It would appear that this 'power assist' function is presently unique to the Victron Phoenix Multi Plus Combi. Because it boosts the output AC, a smaller (more efficient and cost effective) genset can be considered, plus the combi reduces the harmonic distortion of the genset output (which can this can be important for certain sensitive loads such as an induction cookers).
Parallel Connection
Some combis have the ability to be installed in parallel to each other, combining their available output. For example two 2000w combis connected together in parallel will provide 4000w output. Up to 5 combis can be installed on some systems, giving 5 x 2000w = 10Kw output
Efficiency
Most inverters (and combis) run at up to around 90% efficiency. This means that a 1,000w load (say a hair dryer) will in fact take 1,100w out of the battery. This efficiency rating is often the maximum obtained, depending on load applied, the actual power taken from the battery can be considerably more, it is quite possible that the efficiency may be only around 80%, especially when the ambient temperature is high.
Maximum Power / Surge Capacity
A high surge capacity is essential, and should be around three times it's rated output. This is because many appliances (drills, fridge compressors etc.) have a higher start up power requirement. But this 'surge' capacity adds considerably to the manufacturing cost, so some manufacturers limit it.
Low Quiescent Current
When running low power equipment for long periods, such as televisions, videos, refrigerators or computers, it is best to have an inverter with low 'quiescent' current (the actual current the inverter takes to run itself when in operation). This quiescent current can vary dramatically from 0.7 amps for switch mode inverters, 2 -5 amps for transformer inverters and 25 amps for rotary converters. Most combis are switch mode.
A typical portable phone battery on recharge would require about 1 amp an hour for 12 hours, a total of 12 amp/hours. To provide this output a good switch mode inverter would actually use about 15 amp/hours, a transformer based inverter about 40 amp/hours and a rotary converter about 250 amp/hours, all to do the same task.
This information is not clearly available from most companies. Some consume power even when switched off, others consume around 5w when 'on' but under 'no load' conditions. How much power is consumed when just a small load, eg. a 25w fridge is applied is not clear from any of the product specifications, which indicates it is likely higher than the customer thinks!.
Multi Function Relay
Used to start generators or sound alarms based on power demand or battery voltage. Most combis have this function.
IP Protection
The IP number consists of two numbers, the first of which describes the protection against solid bodies, and the second describes the protection given against liquids. IP2x Enclosure provides protection from objects larger than 12 mm. e.g. contact with finger. IP20 - No protection from liquid provided. IP21 - Enclosure provides protection from vertically falling water only. For more information on IP ratings, click here
Remote Controls
If you intend to install you combi inverter in an engine room, or an area that is not accessible on a day to day basis, a remote control needs to be purchased. This is normally an optional extra, costing between £100 and £350). But it needs to be taken into consideration when comparing different unit total costs.
Battery Charger
Most combis have a built in switch mode, multi step, battery charger. Switch mode plus multi step, together with power sharing and a high amp rating are the key features that make a good battery charger.
Switch Mode
Switch mode chargers easily out perform all conventional transformer battery chargers. Eight years ago there were no switch mode chargers on the market, they were all conventional transformer based. However most marine based chargers are now switch mode, but the transformer charger is still cheaper and more reliable than switch mode chargers (because of their poor performance and simple construction). One of the most popular manufacturers of marine battery chargers (Sterling) state that they have spent the last 10 years reducing their failure rate down to below 1%, but do not believe that a switch mode charger could ever be made as reliable as a transformer-based unit, but that the performance of Switch Mode charger units more than compensate for this. Also, because the switch mode output is pure D/C, and not half wave rectified D/C (as per conventional transformer chargers) there is no 50 Hz pulsing, which damage the batteries.
Most (if not all) Combi units have switch mode chargers, but if comparing separate charger units and stand alone inverter units to combis, this needs to be taken into account.
Multi Step Charging
Without question it is now accepted that 3 or 4 step battery charging, is the best way to charge any battery, with adjustable equalizing or absorption time control (depending on battery bank size). In order to do this the charger must have some programmable system to establish what type of batteries you have and what size of battery bank you have. Most (if not all) Combi units have this facility, but if comparing separate charger units and stand alone inverter units to combis, this needs to be taken into account.
Power Pack
The ability of a battery charger to become a power pack is one of the most important parts of marine battery charger, especially for live aboards and those spending considerable time on board.
Most people on boats only require the battery charging aspect of a charger for a relatively small amount of the time that the charger is used, i.e. if you return to your shore supply and plug in your battery charger then the battery charging is done within 5 to 10 hours. The rest of the week the charger must act as a power supply supplying D/C power directly to the boat and not permitting the batteries to be used. When looked at from this perspective, the battery charging aspect is quite small
Most Combis have the built in Power Pack function. This means that after the battery has been charged the power pack mode allows all the D/C power on the boat to be directly produced from the 240 volt input, thus saving the onboard batteries from cycling and premature destruction. This allows the charger to be fitted to a new boat under construction without any batteries onboard. The boat can be wired with only the power pack onboard.
Restricted Power
With larger chargers it is important to be able to restrict their output power, i.e. a 12 volt 100 amp battery charger requires about 2000 watts of power which is about 8 amps. The problem is that you may visit a marina with only a 5 amp supply. This will render your expensive charger useless, unless it has power reduction facilities. Most combis have this facility, some infinitely variable, some with simple 50% / 75% reduction power switching.
Most battery chargers work well at 230 volts, but at many marinas especially at the end of the pontoon the voltage can drop to as low as 180 volts. Most battery chargers will work at these voltages, but ideally look for high input voltage range 180-260 volts and 40-400 Hz frequencies range which offers maximum performance with poor input power supply.
Size of Charger / Batteries and Inverter
Battery charger size is dependent upon battery bank size, the larger the battery bank, the larger the charger needs to be. The battery bank size is dependant upon the inverter size and applied loads. Reading through various reference books and manufacturers information it seems that, as a rule of thumb;-
Battery size needs to be around 20% of the inverter size
Charger needs to be around 25% of battery capacity for optimum fast charging (10% absolute minimum is recommended).
For example a 2500w inverter needs to have a battery bank in the region of around 420ah, which would ideally need a 100a charger, but 42a minimum - at 12v (210ah batteries and 50a charger at 24v). It would seem charging at anything less than 10% and greater than 30% would not be good for the batteries.
However the battery bank size also needs to take into account the power used. Again, reading through various reference books the ‘ Battery capacity should total at least 2.5 and preferably 4 times the anticipated need between charges’. To establish the ‘anticipated need’ between charges an electrical audit / power usage on board needs to be done. I have calculated this (on our 60ft barge) to be 1,400w average per day (3,250w per day worst case – wash m/c, vac, hair dryer etc, and 800w per day minimum – no wash, no vac, no hair dryer etc.). With around 30% usable power from each battery, this equates to needing a 4,700wh battery bank (400ah at 12v).
This analysis is still being worked on, and will be updated as new information becomes available / clearer. If you know of any other useful features built in to some of the Combis please let me know and I will add them to the list, also if you see any errors or poor interpretations, please advise and I will change accordingly.
Again, this is only a guide. Please check with supplier before making a purchase.
It should be noted that I have no practical experience of combis, only of a 150w inverter on a narrowboat connected to 220ah batteries, the reason for putting the data together is to make a judgment on which one suits our needs best. Price will be a deciding factor, as is local availability / installation assistance. With boat fit-out taking us into 2006, there is no real hurry, but may buy if the right offer comes along.
27th October 2004
We have now bought and installed a Victron Phoenix Multiplus 24/3000/70.
1st impression of the Victron is very good, a 'wonderful blue' box'. I have not checked out everything it should do yet, but everything I have checked works well, eg. If on shore power it will increase available 230v supply (say 4, 8 or 16 amp) by another 16 amps from the battery, giving 20, 24 or 32amps, thus enabling simultaneous use of high power electrical appliances, say an electrical kettle (12 amp) and immersion heater (4 amp) and still have lights and battery charging. To my knowledge only the Victron combi can do this, no other combi has this facility. When boiling the electrical kettle, I unplugged the shore power connection and nothing happened, the kettle still continued to boil, 230v lights remained on, as did the mini drinks cooler.... the power switched over to inverter / battery automatically. I have also pluged in my laptop pc into the Victron 'blue box' and can see incoming and outgoing power usage, plus change voltage charging parameters etc.
I have run the combi through a Victron Isolation transformer with auto transfer of power between shore and engine driven Electrolux 230v generator ..... Have not tested / wired up Electrolux yet. But everything else has worked 1st time with no problems. We purchased the Victron Combi (and other equipment) from Energy Solutions, and they came along to check over the installation prior to switching on. Good service, advice and price from Energy Solutions, if you are fitting out around the London area it would be well worth talking over your requirements with them. http://www.energy-solutions.co.uk/

Back to Equipment Pages Replica Dutch Barge Home Page
Created 26th December 2003 - Last updated 18 March 2008

my inverter

2008-05-05T07:58:00.001-07:00

taiyedipo@gmail.com

View my inverters and if beautiful,contact the above address for your own design.My inverters are upto standard and they are constructed and designed with the state of the act facilities.Have a nice day.

Michael Oladipo

DC INVERTER FAQ

2008-05-02T09:04:00.000-07:00

What is an inverter?
How does an inverter work?
Why are most inverters are 115 volts
What size wire, fuse, or breaker will I need?
What is an inverter?
An inverter changes DC voltage from batteries or solar panels, into standard household AC voltage so that it can be used by common tools and appliances.
Converters: What are sometimes called "converters", especially in the RV world, are actually battery chargers and/or DC power supplies. Why they are called converters in RV's and no place else we have not a clue. A "converter" is basically the opposite of an inverter.
Essentially, it does the opposite of what a battery charger or "converter" does. DC is usable for some small appliances, lights, and pumps, but not much else. Most systems should include an inverter of some type, even if it is just an el-cheapo $29 Walmart thing to run the TV occasionally. Some DC appliances are available, with the exception of lights, fans and pumps there is not a wide selection. Most other 12 volt items we have seen are expensive and/or poorly made compared to their AC cousins. The most common battery voltage inputs for inverters are 12, 24, and 48 volts DC - a few models also available in other voltages.
There is also a special line of inverters called a utility intertie or grid tie, which does not usually use batteries - the solar panels or wind generator feeds directly into the inverter and the inverter output is tied to the grid power. The power produced is either sold back to the power company or (more commonly) offsets a portion of the power used. These inverters usually require a fairly high input voltage - 48 volts or more. Some, like the Sunny Boy, go up to 600 volts DC input.
A few grid tie inverters can also be used with batteries, but there will be some loss in overall efficiency for feeding the grid. How much loss can vary considerably, depending on the inverter and the size and type of batteries. If you need battery backup power for a grid tie system, we recommend the Outback Power inverters, as they have the best efficiency with batteries - you will get about a 5-10% loss. With some older inverters, such as the Xantrex SW series, that can sell back excess power to the grid overall losses can be as high as 50%.
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How does an inverter work?
An inverter takes the DC input and runs it into a pair (or more) of power switching transistors. By rapidly turning these transistors on and off, and feeding opposite sides of a transformer, it makes the transformer think it is getting AC. The transformer changes this "alternating DC" into AC at the output. Depending on the quality and complexity of the inverter, it may put out a square wave, a "quasi-sine" (sometimes called modified sine) wave, or a true sine wave.
Square wave inverters are usually only suitable for running some type of electrical tools and motors and incandescent lights. They are pretty rare nowadays, some of the old 1970's Triplite and a few others, and some old military surplus is about the only place you find it now.
Quasi-sine (modified sine, modified square) wave inverters have more circuitry beyond the simple switching, and put out a wave that looks like a stepped square wave - it is suitable for most standard appliances, but may not work well with some electronics or appliances that electronic heat or speed control, or uses the AC for clocks or a timer.
What May Not Run: Appliances that use electronics to control temperature or timers may have problems with modified sine waves. This includes anything - tool or appliance - that is variable speed, bread makers, some microwaves, some washers and dryers that use electronic timing for cycling. Most computers, TV's and similar items will have no problem. Anything with a motor will use about 20% more power with a modified sine wave than with a true sine wave.
Also, some of the chargers used for battery operated tools (such as Makita) may not shut off when the battery is charged, and should not be used with anything but sine wave inverters unless you are sure they will work. Sine wave inverters put out a wave that is the same as you get from the power company - in fact, it is often better and cleaner. Sine wave inverters can run anything, but are also more expensive than other types. The quality of the "modified sine" (actually modified square wave), Quasi-sine wave, etc. can also vary quite a bit between inverters, and may also vary somewhat with the load. The very bottom end put out a wave that is nothing but a square wave, and is too "dirty" for all but universal motor driven tools, coffee makers, toasters, and other appliances that have only a heating element.
One solution to the problem of a few small appliances not working well with modified sine wave inverters is to get a large standard inverter, and a small (such as the Exeltech or Samlex) true sine wave for use only with that equipment. This would also allow you to keep the small appliance (such as an answering machine) powered up without having to run the larger inverter full time.
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Why are most inverters 115 volts?
Most utility connected homes in North America have dual AC voltages - 115 and 230. On a typical home there are three wires coming in - 115-neutral-115. It is 230 volts across the two outside ones. The 115 is used for most things, while 230 is used for water heaters, electric clothes driers, well water pumps, and air conditioning. Since these high-power items are not practical in a solar powered home, they are either not used or are replaced with gas appliances.
Most off-grid homes have little use for 230 volt AC power - but even so many newer ones are wired just like a standard home to meet electrical and building codes. If it IS required, you can "stack" two 115 volt inverters to get 230. The one exception to the above is that many AC well pumps are 230 volt. If the well pump is the only 230 volt item you have, the best choice is probably to get a step up transformer, such as the Xantrex or Outback Power 120 to 240 step up transformer.
There are export versions of most inverters for 100 volts, 105 volts, 205 volts, and 220/230 volts, in both 50 and 60 Hz.
Inverter-Chargers:
Inverters come in two basic types - with and without built in battery chargers. The ones with built in chargers are handy if you charge your batteries from AC, especially for RV's. They are also essential if using an inverter for setting up a UPS system for backup power. But not everyone needs them - and most small inverters under 1000 watts or so are simply not available with a built in charger.
Nearly all inverter-chargers made in the past few years have 3-stage chargers, so you can usually leave them powered up all the time. Nearly all inverters with chargers also have a built in transfer relay - what that means is that if you are running from AC or shore power, the power feeds through the inverter, with some being tapped off for the battery charger. If the AC power goes out, the inverter automatically switches to battery power. In most cases you won't even see a light flicker, it is so fast.
Inverter (and other) Efficiency:
Inverter efficiency is a question we get asked about a lot. The efficiency of an inverter has to do with how well it converts the DC voltage into AC. This usually ranges from 85% to 95%, with 90% being about average.
However, there is more to the story. Efficiency ratings are usually given into a resistive load (basically something like a light bulb or electric heater). When running such things as motors, the efficiency actually breaks down into two parts - the efficiency of the inverter, and the efficiency of the waveform. Waveform efficiency means that most motors and many electronic appliances run better and use less power with a sine wave. Typically, an electric motor (such as a pump or refrigerator) will use from 15% to 20% more power with a modified sine wave than with a true sine wave. When choosing an inverter based on efficiency, you should also consider what you are going to be running.
A 90% efficient modified sine wave inverter is not 90% when running a compressor motor, for example, because electric motors are less efficient. They use about 20% more power on a modified sine wave.
Inverters are also much less efficient when used at the low end of their maximum power. For example, using a 1000 watt inverter to power a 20 watt radio may actually be using 30 to 40 watts from the battery, as the inverter itself is eating up a lot just to run. Most inverters are most efficient in the 30% to 90% power range.
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What size wire, fuse, or breaker will I need?
Inverters have two or three sets of power carrying wires to be concerned about: the wires from the battery to the inverter, the wires from the inverter to the home (or other AC load), and in some cases the wiring from a backup generator or other AC source. The wiring for the AC to the home and from the generator is sized just like you would for AC wiring in a utility connected home. It is usually #10, 12, or 14 standard AC wire. For the small inverters, 800 watts or less, #16 can be used but the mechanical strength of small wire leaves much to be desired.
The wire or cables from the batteries to the inverter are much more critical, and are often undersized. In some cases, the cable may be large enough to carry the "static" load of a motor, but on start up will drop so much voltage in the cable that the inverter will shut down on low voltage cutoff. The same thing can happen with small inverters and TV sets - a TV may only use 100 watts, but the start up surge may be 300 watts for a few seconds. Wire lengths from the battery should always be kept as short as possible, but not so tight that there is a strain on the connections.

Recommended Fuses, Breakers, and Wire Sizes for Inverters

200-250	12	20 amp	12 to 14
300-500	12	30-40 amp	8 to 10
600-1000	12	50-60 amp	6 to 8
110-1500	12	110 amp	4 to 6
1100-1500	12	200 amp/175 bkr	2/0 to 2
1800-2500	24	110 amp	2/0 to 4
1800-2500	12	300 to 400 amp/250	4/0
2600-3600	24	200 amp/175	2/0
4000	24	400 amp/250	4/0
5000	24	400 amp/250	4/0
5500	48	200 amp/175	2/0

These are the recommended cable sizes for a ten-foot distance from the batteries to the inverter. Note that the larger wire size is the recommended, the smaller wire size is the absolute minimum for safe operation. The sizes recommended are from a combination of maximum wire amperage capacity and voltage drop. You can't go wrong using bigger wire.The fuse and breaker sizes shown are approximate. Since transformer based (Outback Power, Xantrex) inverters usually have a much higher maximum surge rating than electronic based (Samlex, Exeltech, Statpower), they should always use the larger if more than one size is shown. The reason some show a smaller breaker size than fuse size is that breakers do not blow as fast on a temporary surge

The fuse should NEVER be bigger than 125% of the maximum surge power of the inverter. For example, an inverter is rated at 1000 watts, and 1800 watts surge. For a 12 volt inverter, divide 1800 by 12, which gives you 150. 150 x 1.25 = 190 amp. The nearest standard size fuse is 200 amp. You are always safe going to a smaller fuse, but if too small it might blow on heavy loads. DC breakers should be rated for about the maximum amperage draw, as they have a slight time delay on over current.
Which inverter has the best sine wave?
In general, from best down, it is Exeltech, Outback Power, Statpower, Samlex. All are good enough for 99% of all applications, but the Exeltech may be better for low power critical applications, such as recording or studio vans, or noise sensitive medical equipment. For higher power systems that need the best sine wave, either the Outback Power series or the Xantrex SW+ series.

Which is the "best" inverter?
There is no "best" for all purposes. Although the Outback Power & Xantrex are considered by many to be the top of the line, it does not make sense to spend $500 to $3000 when all you need is a little Statpower Prowatt or Exeltech 125 watt sine wave to power up a laptop. The best way to decide on what inverter is best is to work backwards - figure out what you are going to use it for, and then find one that fits those requirements. Also, some inverters have built in chargers, which may be needed in some systems. The Outback & Xantrex sine wave units include software and hardware for remote generator start, alarms, remote control and monitoring, computer data, and other functions - in many applications this is very important. If you are running pumps or other large motors, Xantrex or Outback are the only one we will recommend, even though some others might work.

555 Timer(Astable Multivibrator Circuit)

2008-05-02T08:57:00.000-07:00

NE555 is composed of the voltage comparators, the flip-flop and the transistor for the discharge. The composition is simple, but it is excellent one.Three resistors are connected with the inside in series and the power supply voltage(Vcc) is divided in 3. This composition is an excellent point. 1/3 with power supply voltage is applied to the positive input terminal of the comparator (COMP1) and the voltage of 2/3 is applied to the negative terminal of the comparator (COMP2). When the voltage of the trigger terminal(TRIGGER) is less than 1/3 of the power supply voltage, the S terminal of the flip-flop(FF) becomes H level and an FF is set. When the voltage of the threshold terminal(THRESHOLD) is more than 2/3 of the power supply voltage, the R terminal of the FF becomes H level and an FF is reset.
The oscillation operation explanation
I will explain the circuit operation below. The condition immediately after the turning on

Immediately after a power supply voltage is supplied, as for the FF, the Q becomes H and becomes L condition. Because is the L, TR is in the OFF condition and the electric current flows through the resistor of Ra and the Rb at the capacitor (C). Immediately after a power supply voltage is supplied, the electric charge isn't stagnant in capacitor(C). So the voltage of the X point starts from 0V. Because the X point is lower than V1 of COMP1, the S terminal of the FF becomes the H condition. With this, the Q becomes H, becomes L condition but they are in the condition already. On the other hand, because the COMP2 (+) terminal is lower than V2, the output of COMP2 becomes the L and the FF is stable in this condition.

Output's reverse (1)

When the voltage of the X point crosses V1 of COMP1, the output of COMP1 becomes L. However, this change doesn't change the condition of the FF. The output of COMP2 becomes the H condition when the voltage of the X point rises more and reaches V2 of COMP2. With this, the R terminal of the FF becomes H and the output state of the FF reverses. The Q becomes the L condition and becomes the H condition. At this time, OUT changes into the L from H. Because became the H condition, TR becomes the ON condition. Because the interface of Ra and the Rb becomes the grounded condition, the electric current which was flowing through C so far through Ra and the Rb gets not to flow through capacitor(C). The electric charge which was stagnant in capacitor(C) begins the discharge through the Rb and TR. Voltage of the X point begins to go down with this discharge. Because voltage of the X point goes down, the voltage of the COMP2 (+) terminal becomes less than V2 and the R terminal of the FF changes into the L condition from H. This change doesn't change the condition of the FF.It is only in a little time that the R terminal of the FF becomes the H condition.

Output's reverse (2)

Because TR becomes ON, as for the electric charge of capacitor(C), it continues the discharge and the voltage of the X point falls. When the voltage of the X point becomes equal to or less than V1 of COMP1, the output of COMP1 becomes the H condition and the S terminal of the FF becomes the H condition. This changes the Q of the FF to H and changes into the L condition. Because became the L condition, TR becomes the OFF condition and the discharge from capacitor(C) stops. The electric current flows through Ra and the Rb again in capacitor(C) and the electric charge begins to store up. When the electric charge begins to store up in capacitor(C), voltage of the X point begins to go up and the output of COMP1 becomes the L condition immediately. After that, it repeats this operation and the signal of the square wave is output.When charging (accumulating the electric charge) capacitor(C), the electric current flows through Ra and the Rb and in case of the discharge (missing the electric charge), it passes only the Rb. So, the time of the charging and the time of the discharge are different. By making the Rb compared with Ra big, the difference of both becomes small but can not make the same at all. To make the same, it is good if Ra is 0 ohm, but in the case, Vcc is directly connected with TR and TR has broken. Don't make Ra = 0 ohm absolutely. If doing the ratio of Ra and the Rb by several times, in case of the practical use, there is not a problem.

sine/cosine wave inverter circuit

2008-05-02T08:51:00.000-07:00

Sine/cosine wave inverter circuit
I introduce the oscillator which outputs the Sine wave and the Cosine wave at the same time using the operational amplifier.Because the distortion was big at the circuit to have been introducing before, I improved at the circuit with little distortion.The circuit this time combines the integration circuit and the inverter by the operational amplifier.The 90 degree phase is shifted about the sine wave and the cosine wave. The sine wave is the signal to be 90 degree delayed from the cosine wave.
In case of C=C1=C2, R=R4=R5, the oscillation frequency can be calculated by the following formula.
The example of the circuit which was made this time is shown below.=

F=1/(2 x 3.14 x 0.001 x 10-6 x 15 x 103)
=1/(0.0942 x 10-3)
=10.62 x 103
=10.62 KHz
The frequency in the actual circuit was to 10.585 KHz be.

Waveform generated as one seen from the oscilloscope

Sine Wave Oscillator

2008-05-02T08:37:00.000-07:00

Sine wave oscillator
I introduce the sine wave oscillator which used the operational amplifier in this page.The Wien bridge sine wave oscillator to introduce is the oscillator which works in the oscillation by returning(positive feedback) the oscillation output to the input.Because there are few parts, the Wien bridge oscillator is the often used circuit.The point of this circuit is the negative feedback circuit to make the oscillation operation be stable. The circuit to be using this time changes the resistance value of the Field Effect-type Transistor(FET) at the d.c. voltage which rectified the oscillation output in the full wave and is making the oscillation operation be stable. The sine wave oscillator is the oscillator which is difficult to make because the distortion of the oscillation signal occurs compared with the square wave oscillator, the triangular wave oscillator.
In case of C=C1=C2, R=R1=R2, the oscillation frequency can be calculated by the following formula.
The example of the circuit which was made this time is shown below.
f
=
1/(2 x 3.14 x 0.01 x 10-6 x 15 x 103)
=
1/(0.942 x 10-3)
=
1.062 x 103
=
1,062 HzThe frequency in the actual circuit was to 900 Hz be.You can change the frequency when you change C1, C2, R1 and R2 of the circuit diagram. In the relation of the balance at the bridge, you had better make C1=C2, R1=R2.Even if it is different little, it is possible to oscillate.
I am explaining the following contents in the page of the explanation.
The sine wave is what?
The principle of the oscillator
The principle of the Wien bridge oscillation circuit
The amplitude control of the Wien bridge oscillation
Pattern drawing Operation explanation

inverter using IC 4069UB

2008-05-02T08:10:00.000-07:00

DC/AC inverter (2)
On this page, I will explain DC/AC invertor with center-tapless transformer.As for the DC/AC invertor with center-tap transformer, refer to "DC/AC invertor (1)".The invertor that I made this time uses power MOS FET as swtching device. I assum that this unit is used with the battery of car. So, the input voltage is +12V DC. The output voltage is AC 100V. However, input and output voltages aren't limited to this. You can use any voltage. They depend on the transformer to use. The wave form of the output is square wave. In my experience, it is usable with a lot of home electronics equipment. The electric power which is possible to handle is decided by the transformer to use. This time, I am using the transformer with 12V-10A(secondary side). So, it is possible to handle 120VA(about 100W).I was asked about 220V output from some readers. The output voltage of the inverter is decided only in the transformer. You can use the transformer with 220V as for primary(input) and 12V as for secondary(output). At my circuit, primary and secondary should be used oppositely. Then, you will be able to get AC220V from DC12V.
FUSE must be put, because the excessive input current flows when the oscillator stops.

Circuit drawingof DC/AC inverter (2)

Circuit explanation of DC/AC inverter (2)

The square wave oscillatorThis is the square wave oscillator which used a CMOS-type logic inverters. I use the word "logic inverter" to avoid confusion with the DC/AC inverter. The output of the oscillator is connected with the drive circuit through the logic inverters. The antiphase signal of the alternating current is created using the logic inverter, too. Connect the input of the logic inverters not to be using with the grounding to avoid bad influence.As for the operation of the oscillator which used logic inverters, refer to "Square wave oscillator (2)".I chose resistance and capacitor for the oscillator in the following value. I calculated that it was possible to set to 50 Hz or 60 Hz with the variable resistor. Because there is an error of the part in the actual circuit, it is a reference value.
Minimum frequency
F= 1/( 2.2 x C x R )
= 1/( 2.2 x 2.2 x 10-6 x 4.2 x 103 )
= 1/( 20.328 x 10-3 )
= 49.2 Hz

Maximum frequency
F= 1/( 2.2 x C x R )
= 1/( 2.2 x 2.2 x 10-6 x 2.2 x 103 )
= 1/( 10.648 x 10-3 )
= 93.9 Hz

In the measurement result in the actual circuit,the minimum frequency was 43.6 Hz and the maximum frequency was to 76.6 Hz be.
The FET drive circuitBecause the output of the oscillator is the TTL of 0V to 5V, it is converted into the amplitude of vibration of 0V to 12V to drive an FET with this circuit. It is not a special circuit.

The power MOS FET switching circuitThis is the switching circuit which is the main circuit of the DC/AC inverter this time. I used C-MOS FET circuit by power MOS FET. Two sets of C-MOS FET circuits are used and are controlled by the antiphase.
In case of the input of TR3 and TR4 are L level and the input of TR5 and TR6 are H level, TR3 and TR6 become ON condition and TR4 and TR5 become OFF condition. Therefore, the electric current flows through the direction of A to B to the secondary coil(12V side) of the transformer.When the input level is opposite, TR3 and TR6 become OFF condition and TR4 and TR5 become ON condition. Therefore, the electric current which flows through the transformer becomes contrary to the case of the above.Either above-mentioned condition is continued when the oscillator stops. Therefore, the big electric current flows on the secondary side of the transformer. The fuse must be put to protect.Refer to "The operation principle of C-MOS FET" about MOS FET and the C-MOS circuit.
The +5V power circuitThis is the circuit which is used 3 terminal regulator for +5V. It is OK with the 100mA type because it is only to drive IC1.

Multivibrator

2008-05-02T07:56:00.000-07:00

A-stable multivibrator(TR type)
I will introduce the a-stable multivibrator circuit which used two transistors.The a-stable multivibrator is the circuit which repeats the high level (H) condition and the low level (L) condition alternately.‚hIn case of the transistor type, the voltage (Vcc) of the power supply can be comparatively freely set compared with the IC type. Also, it is possible to assemble compactly compared with the IC type when considering the power circuit and so on, too.However, because VEB is a maximum of 5V in the case of a transistor called 2SC1815 used this time, as supply voltage, it's to 5V. For details, please look at circuit explanation.

Calculation of the blink periodfor A-stable multivibrator (TR type)
The period which repeats a blink is fixed by the value of capacitor (Cx) and resistor (Rx), and capacitor (Cy) and resistor (Ry). The half period time (t) is possible to calculate by the following formula. The half period is the time which is made H condition or an L condition.It uses a calculation formula on the side of TR1 as an example.t : second, Cx : Farad, Rx : ohmA repeat period is decided by the combination of Cx and Rx, and Cy and Ry.In case of Cx, Cy=47 µF, Rx, Ry=22 k-ohm, it is as follows.
The time that TR1 becomes OFF condition (t1)
t1= 0.69 * Cx * Rx= 0.69 * 47 * 10-6 * 22 * 103= 0.713 secondsTR2(t2) is similar. The frequency (f)
F= 1 / ( t1+t2 ) = 1 / ( 0.7 + 0.7 )= 0.71 Hz
The measurement frequency of the circuit which was made this time was to 0.78 Hz be.The error with the calculation value is for the error of the part and the characteristic of the transistor and so on. The measurement value of Cx, Cy was to approximately 47 µF be. The measurement value of Rx and Ry was to about 20 k-ohm be. When calculating with this value, the frequency becomes about 0.77 Hz. The calculation value and the measurement value are an near value.Don't expect a correct period with this circuit. The period changes with the temperature around. So, this circuit isn't possible to use for the circuit with strict period.

I need an inverter

2008-04-23T06:04:00.000-07:00

If you need an inverter design of any capacity that can meet your load demand,please send all correspondence to taiyedipo@gmail.com or call mobile numbers: 08055081359,08064272866. You may contact this email:olamicspirit2003_ng@yahoo.com also.

Thank you

What can an inverter do for you

2008-04-23T06:03:00.000-07:00

Inverter
Inverter power is a great way to provide reliable electricity to many applications. We have an inverter in our Garage, our car, our boat, and our RV. We have even used an Inverter to run a pinic in the middle of a baseball diamond. Inverters are so versatile because they allow you to turn readily available DC power into the more desired AC power. So whenever you need remote power, what can an Inverter Do For You?

Inverter Power Can Really Handle Emergency Outages
Many times we have power outages, we want to run a TV or radio to find out what is happening in the world around us. This is hard to do if you do not have a battery powered product. With an Inverter you can run most small low load AC devices using your car battery in an emergency. A power inverter will convert your cars battery power to 120 Volts AC power. This will allow you to plug in your TV and see whats going on.

Camera Charged By Inverter on Turtle Hospital Visit
We went to the Florida Keys in late January and Early February 2008. We stopped at the Turtle hospital in Marathon. This place rocks!!!! Read more on how an inverter helped us capture some great pictures!

DC to DC converters

2008-04-23T05:52:00.000-07:00

Variable 3 - 24 Volt / 3 Amp Power Supply
This regulated power supply can be adjusted from 3 to 25 volts and is current limited to 2 amps as shown, but may be increased to 3 amps or more by selecting a smaller current sense resistor (0.3 ohm). The 2N3055 and 2N3053 transistors should be mounted on suitable heat sinks and the current sense resistor should be rated at 3 watts or more. Voltage regulation is controlled by 1/2 of a 1558 or 1458 op-amp. The 1458 may be substituted in the circuit below, but it is recommended the supply voltage to pin 8 be limited to 30 VDC, which can be accomplished by adding a 6.2 volt zener or 5.1 K resistor in series with pin 8. The maximum DC supply voltage for the 1458 and 1558 is 36 and 44 respectively. The power transformer should be capable of the desired current while maintaining an input voltage at least 4 volts higher than the desired output, but not exceeding the maximum supply voltage of the op-amp under minimal load conditions. The power transformer shown is a center tapped 25.2 volt AC / 2 amp unit that will provide regulated outputs of 24 volts at 0.7 amps, 15 volts at 2 amps, or 6 volts at 3 amps. The 3 amp output is obtained using the center tap of the transformer with the switch in the 18 volt position. All components should be available at Radio Shack with the exception of the 1558 op-amp.

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Variable Voltage and Current Power Supply
Another method of using opamps to regulate a power supply is shown below. The power transformer requires an additional winding to supply the op-amps with a bipolar voltage (+/- 8 volts), and the negative voltage is also used to generate a reference voltage below ground so that the output voltage can be adjusted all the way down to 0. Current limiting is accomplished by sensing the voltage drop across a small resistor placed in series with the negative supply line. As the current increases, the voltage at the wiper of the 500 ohm pot rises until it becomes equal or slightly more positive than the voltage at the (+) input of the opamp. The opamp output then moves negative and reduces the voltage at the base of the 2N3053 transistor which in turn reduces the current to the 2N3055 pass transistor so that the current stays at a constant level even if the supply is shorted. Current limiting range is about 0 - 3 amps with components shown. The TIP32 and 2N3055 pass transistors should be mounted on suitable heat sinks and the 0.2 ohm current sensing resistor should be rated at 2 watts or more. The heat produced by the pass transistor will be the product of the difference in voltage between the input and output, and the load current. So, for example if the input voltage (at the collector of the pass transistor) is 25 and the output is adjusted for 6 volts and the load is drawing 1 amp, the heat dissipated by the pass transistor would be (25-6) * 1 = 19 watts. In the circuit below, the switch could be set to the 18 volt position to reduce the heat generated to about 12 watts.

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2 Watt Switching Power Supply
In this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor. Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off. The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts. Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode. The efficiency is about 80% using a high Q inductor.

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Whistle On - Whistle Off

This is an extension of the CMOS toggle flip flop circuit shown in the "Circuits controlling relays" section with the addition of two bandpass filters and condenser microphone so the relay can be toggled by whistling at it. The condender mic used is a PC board mount Radio Shack #270-090C. The filters are tuned to about 1700 Hz, or the third Ab above middle C on a piano keyboard which is a fairly easy note for me to whistle. Resistor values for the filter can be computed using the three formulas below but we need to assume a gain and Q factor for the filter and the Q of the circuit must be greater than the square root of (Gain/2). The microphone produces only a couple millivolts so the overall gain needs to be around 4000 or around 65 for each filter. The Q or quality factor is the ratio of the center frequency to the bandwidth (-3dB points) and was chosen to be 8 which is greater than 5.7 which is the minimum value for a gain of 65. Both capacitor values need to be the same for easy computation of the resistor values and were chosen to be 0.01uF which is a common value and usable at audio frequencies. From those assumptions, the resistor values can be worked out from the following formulas.
R1 = Q/(G*C*2*Pi*F) = 8/(65*.01^-6*6.28*1700) = 1152 or 1.1K
R2 = Q / ((2*Q^2)-G)*C*2*Pi*F) = 8/((128-65)*.01^-6*6.28*1700)= 1189 or 1.2K
R3 = (2*Q)/(C*2*Pi*F) = 16/(.01^6*6.28*1700) = 150K

The op-amps are biased using a voltage divider of two 10K resistors so the output will be centered around half the supply voltage or 6 volts. The output of the second filter charges a 1uF cap at the base of a NPN transistor (2N3904 or similar). The emitter voltage is biased at 6.6 volts using the 3.3K and 2.7K resistors so that the transistor will conduct and trigger the flip flop when the peak signal from the filter reaches 8 volts. The 8 volt figure is the emitter voltage (6.6) plus the emitter base voltage drop (0.7) plus the diode drop (0.7). The sensitivity can be adjusted by changing the value of either the 2.7K or 3.3K resistors so that more or less signal amplitude is needed to trigger the flop flop.

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DC to DC Converter

The circuit below is a DC to DC converter using a standard 12 VAC center tapped power transformer wired as a blocking oscillator. The circuit is not very efficient but will produce a high voltage usable for low power applications. The input battery voltage is raised by a factor of 10 across the transformer and further raised by a voltage tripler consisting of three capacitors and diodes connected to the high voltage side of the transformer. The circuit draws about 40 milliamps and should operate for about 200 hours on a couple of 'D' alkaline batteries. Higher voltages can be obtained by reducing the 4.7K bias resistor. More information on blocking oscillators can be found here: Blocking Oscillators

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120 VAC Lamp Dimmer
The full wave phase control circuit below was found in a RCA power circuits book from 1969. The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting. The time delay from the beginning of each half cycle to the point where the SCR switches on is controlled by the 50K resistor which adjusts the time required for the 2uF capacitor to charge to 8 volts. As the resistance is reduced, the time is reduced and the SCR will conduct earlier during each half cycle which applies a greater average voltage across the load. With the resistance set to minimum the SCR will trigger when the voltage rises to about 40 volts or 15 degrees into the cycle. To compensate for component tollerances, the 15K resistor can be adjusted slightly so that the output voltage is near zero when the 50K pot is set to maximum. Increasing the 15K resistor will reduce the setting of the 50K pot for minimum output and visa versa. Be careful not to touch the circuit while it is connected to the AC line.

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Varying brightness AC lamp
In this circuit, an SCR is used to slowly vary the intensity of a 120 volt light bulb by controlling the time that the AC line voltage is applied to the lamp during each half cycle.

Caution:

The circuit is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the circuit while it is connected to the AC power line. A 2K, 10 watt power resistor is used to drop the line voltage down to 9 volts DC. This resistor will dissipate about 7 watts and needs some ventilation.

Operation:

A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum which corresponds to about 7 milliseconds of delay, or most of the half cycle time so that the lamp is almost off. Full brightness is obtained on the sixth count (pin 1) which is not connected so that the current will be maximum and provide a minimum delay and trigger the SCR near the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down between maximum and minimum. Each step up or down provides about twice or half the power, so that the intensity appears to change linearly. The brightness of each step can be adjusted with the 4 resistors (4.3K, 4.7K, 5.6K, 7.5K) connected to the counter outputs.
The circuit has been built by Don Warkentien (WODEW) who suggsted adding a small 47uF capacitor from ground to the junction of the current source transistor (PNP) to reduce the digital stepping effect so the lamp will brighten and fade in a smoother fashion. The value of this capacitor will depend on the 4017 counting rate, a faster rate would require a smaller capacitor.

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oscillators

2008-04-23T05:35:00.000-07:00

Inverter (logic gate)
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For the electrical power inverter, see Inverter (electrical).

Static CMOS InverterIn digital logic, an inverter is a logic gate which inverts the digital signal driven on its input. It is also called NOT gate. The truth table of the gate is as follows:

The truth table for inverter input output
0 1
1 0

This represents perfect switching behavior, which is the defining assumption in Digital electronics. In practice, actual devices have electrical characteristics that must be carefully considered when designing inverters. In fact, the non-ideal transition region behavior of a CMOS inverter makes it useful in analog electronics as a class A amplifier (e.g., as the output stage of an operational amplifier[1]).

Contents [hide]
1 Electronic implementation
1.1 Performance measurement
1.2 Digital building block
1.3 External links
1.4 References

[edit] Electronic implementation

Schematic of a Saturated-Load Digital InverterAn inverter circuit outputs a voltage representing the opposite logic-level to its input. Digital electronics are circuits that operate at fixed voltage levels corresponding to a logical 0 or 1 (see Binary). An inverter circuit serves as the basic logic gate to swap between those two voltage levels. Implementation determines the actual voltage, but common levels include (0, +5V) for TTL circuits.

Common types include resistive-drain, using one transistor and one resistor; and CMOS, which uses two (opposite type) transistors per inverter circuit

[edit] Performance measurement
Digital inverter quality is often measured using the Voltage Transfer Curve, which is a plot of input vs. output voltage. From such a graph, device parameters including noise tolerance, gain, and operating logic-levels can be obtained.

Voltage Transfer Curve for a 20 μm Inverter constructed at North Carolina State UniversityIdeally, the voltage transfer curve (VTC) appears as an inverted step-function - this would indicate precise switching between on and off - but in real devices, a gradual transition region exists. The VTC indicates that for low input voltage, the circuit outputs high voltage; for high input, the output tapers off towards 0 volts. The slope of this transition region is a measure of quality - steep (close to -Infinity) slopes yield precise switching.

The tolerance to noise can be measured by comparing the minimum input to the maximum output for each region of operation (on / off).

The output voltage, VOH, can be a measure of signal driving strength when cascading many devices together.

[edit] Digital building block
The digital inverter is considered the base building block for all digital electronics. Memory (1 bit register) is built as a latch by feeding the output of two serial inverters together. Multiplexers, decoders, state machines, and other sophisticated digital devices all rely on the basic inverter.

The Hex Inverter is an integrated circuit that contains six (hexa-) inverters. For example, the 7404 TTL chip and the 4049 CMOS chip each have 14 pins, 2 of which are used for power/referencing, and the remaining 12 pins are used by the inputs and outputs of the six inverters.

inverter project design

2008-04-23T05:19:00.000-07:00

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DC to AC power inverters
Power or electrical energy is usually stored in batteries. Batteries can only give Direct Current (DC) and not Alternating Current (AC).

DC AC power inverter

So, the problem arises when you need to take power that has been stored in a battery or bank of batteries, and use it to run electrical appliances that are AC and not DC.

The answer to this, is to use a DC to AC power inverter.

The inverter is the main component of any independent power system which requires AC power. The power inverter will convert the DC power stored in the batteries and into Ac power to run conventional appliances.

Inverters

Just over a decade or so ago, DC AC power inverters were so inefficient and unreliable, many people restricted themselves to 12V lights and appliances.

If you have recently tried to shop around for 12V DC appliances, you will see that there is a very limited selection available.

Today, the efficiency and reliability of the latest DC AC power Inverters, are a far cry from the inverters that were available 15 to 20 years ago.

There are three waveforms produced by modern solid state power inverters. The simplest, a square wave power inverter, used to be all that was available. Today, these are very rare, as many appliances will not operate on a square wave.

For ease of reference, we have categorized our comprehensive DC to AC power inverter range into into simple subheadings that should make it a lot easier for you to find the specific size, type and rating of power inverter to suit your specific need and application:

Modified sine wave power inverter
Pure sine wave power inverter
Power inverters for 4x4
Power inverters for laptop
Backup inverter power for your home
Backup inverter power for your office
Solar inverters
Inverters with generator transfers
If you would like to know more about the types of DC to AC power inverters available today, click on either “modified sine wave” or “true sine wave” button to find out all you can about our DC AC power inverters.

Keywords for this page:

Inverter, Inverters, Power inverter, power inverters

Copyright © 2005 - 2007 Plan-My-Power (PTY) ltd

Inverters

2008-04-23T04:58:00.000-07:00

What is an inverter?
How does an inverter work?
Why are most inverters are 115 volts
What size wire, fuse, or breaker will I need?

What is an inverter?
An inverter changes DC voltage from batteries or solar panels, into standard household AC voltage so that it can be used by common tools and appliances.

Converters: What are sometimes called "converters", especially in the RV world, are actually battery chargers and/or DC power supplies. Why they are called converters in RV's and no place else we have not a clue. A "converter" is basically the opposite of an inverter.

Essentially, it does the opposite of what a battery charger or "converter" does. DC is usable for some small appliances, lights, and pumps, but not much else. Most systems should include an inverter of some type, even if it is just an el-cheapo $29 Walmart thing to run the TV occasionally. Some DC appliances are available, with the exception of lights, fans and pumps there is not a wide selection. Most other 12 volt items we have seen are expensive and/or poorly made compared to their AC cousins. The most common battery voltage inputs for inverters are 12, 24, and 48 volts DC - a few models also available in other voltages.

There is also a special line of inverters called a utility intertie or grid tie, which does not usually use batteries - the solar panels or wind generator feeds directly into the inverter and the inverter output is tied to the grid power. The power produced is either sold back to the power company or (more commonly) offsets a portion of the power used. These inverters usually require a fairly high input voltage - 48 volts or more. Some, like the Sunny Boy, go up to 600 volts DC input.

A few grid tie inverters can also be used with batteries, but there will be some loss in overall efficiency for feeding the grid. How much loss can vary considerably, depending on the inverter and the size and type of batteries. If you need battery backup power for a grid tie system, we recommend the Outback Power inverters, as they have the best efficiency with batteries - you will get about a 5-10% loss. With some older inverters, such as the Xantrex SW series, that can sell back excess power to the grid overall losses can be as high as 50%.

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How does an inverter work?
An inverter takes the DC input and runs it into a pair (or more) of power switching transistors. By rapidly turning these transistors on and off, and feeding opposite sides of a transformer, it makes the transformer think it is getting AC. The transformer changes this "alternating DC" into AC at the output. Depending on the quality and complexity of the inverter, it may put out a square wave, a "quasi-sine" (sometimes called modified sine) wave, or a true sine wave.

Square wave inverters are usually only suitable for running some type of electrical tools and motors and incandescent lights. They are pretty rare nowadays, some of the old 1970's Triplite and a few others, and some old military surplus is about the only place you find it now.

Quasi-sine (modified sine, modified square) wave inverters have more circuitry beyond the simple switching, and put out a wave that looks like a stepped square wave - it is suitable for most standard appliances, but may not work well with some electronics or appliances that electronic heat or speed control, or uses the AC for clocks or a timer.

What May Not Run: Appliances that use electronics to control temperature or timers may have problems with modified sine waves. This includes anything - tool or appliance - that is variable speed, bread makers, some microwaves, some washers and dryers that use electronic timing for cycling. Most computers, TV's and similar items will have no problem. Anything with a motor will use about 20% more power with a modified sine wave than with a true sine wave.

Also, some of the chargers used for battery operated tools (such as Makita) may not shut off when the battery is charged, and should not be used with anything but sine wave inverters unless you are sure they will work. Sine wave inverters put out a wave that is the same as you get from the power company - in fact, it is often better and cleaner. Sine wave inverters can run anything, but are also more expensive than other types. The quality of the "modified sine" (actually modified square wave), Quasi-sine wave, etc. can also vary quite a bit between inverters, and may also vary somewhat with the load. The very bottom end put out a wave that is nothing but a square wave, and is too "dirty" for all but universal motor driven tools, coffee makers, toasters, and other appliances that have only a heating element.

One solution to the problem of a few small appliances not working well with modified sine wave inverters is to get a large standard inverter, and a small (such as the Exeltech or Samlex) true sine wave for use only with that equipment. This would also allow you to keep the small appliance (such as an answering machine) powered up without having to run the larger inverter full time.

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Why are most inverters 115 volts?
Most utility connected homes in North America have dual AC voltages - 115 and 230. On a typical home there are three wires coming in - 115-neutral-115. It is 230 volts across the two outside ones. The 115 is used for most things, while 230 is used for water heaters, electric clothes driers, well water pumps, and air conditioning. Since these high-power items are not practical in a solar powered home, they are either not used or are replaced with gas appliances.

Most off-grid homes have little use for 230 volt AC power - but even so many newer ones are wired just like a standard home to meet electrical and building codes. If it IS required, you can "stack" two 115 volt inverters to get 230. The one exception to the above is that many AC well pumps are 230 volt. If the well pump is the only 230 volt item you have, the best choice is probably to get a step up transformer, such as the Xantrex or Outback Power 120 to 240 step up transformer.

There are export versions of most inverters for 100 volts, 105 volts, 205 volts, and 220/230 volts, in both 50 and 60 Hz.

Inverter-Chargers:
Inverters come in two basic types - with and without built in battery chargers. The ones with built in chargers are handy if you charge your batteries from AC, especially for RV's. They are also essential if using an inverter for setting up a UPS system for backup power. But not everyone needs them - and most small inverters under 1000 watts or so are simply not available with a built in charger.

Nearly all inverter-chargers made in the past few years have 3-stage chargers, so you can usually leave them powered up all the time. Nearly all inverters with chargers also have a built in transfer relay - what that means is that if you are running from AC or shore power, the power feeds through the inverter, with some being tapped off for the battery charger. If the AC power goes out, the inverter automatically switches to battery power. In most cases you won't even see a light flicker, it is so fast.

Inverter (and other) Efficiency:
Inverter efficiency is a question we get asked about a lot. The efficiency of an inverter has to do with how well it converts the DC voltage into AC. This usually ranges from 85% to 95%, with 90% being about average.

However, there is more to the story. Efficiency ratings are usually given into a resistive load (basically something like a light bulb or electric heater). When running such things as motors, the efficiency actually breaks down into two parts - the efficiency of the inverter, and the efficiency of the waveform. Waveform efficiency means that most motors and many electronic appliances run better and use less power with a sine wave. Typically, an electric motor (such as a pump or refrigerator) will use from 15% to 20% more power with a modified sine wave than with a true sine wave. When choosing an inverter based on efficiency, you should also consider what you are going to be running.

A 90% efficient modified sine wave inverter is not 90% when running a compressor motor, for example, because electric motors are less efficient. They use about 20% more power on a modified sine wave.

Inverters are also much less efficient when used at the low end of their maximum power. For example, using a 1000 watt inverter to power a 20 watt radio may actually be using 30 to 40 watts from the battery, as the inverter itself is eating up a lot just to run. Most inverters are most efficient in the 30% to 90% power range.

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What size wire, fuse, or breaker will I need?
Inverters have two or three sets of power carrying wires to be concerned about: the wires from the battery to the inverter, the wires from the inverter to the home (or other AC load), and in some cases the wiring from a backup generator or other AC source. The wiring for the AC to the home and from the generator is sized just like you would for AC wiring in a utility connected home. It is usually #10, 12, or 14 standard AC wire. For the small inverters, 800 watts or less, #16 can be used but the mechanical strength of small wire leaves much to be desired.

The wire or cables from the batteries to the inverter are much more critical, and are often undersized. In some cases, the cable may be large enough to carry the "static" load of a motor, but on start up will drop so much voltage in the cable that the inverter will shut down on low voltage cutoff. The same thing can happen with small inverters and TV sets - a TV may only use 100 watts, but the start up surge may be 300 watts for a few seconds. Wire lengths from the battery should always be kept as short as possible, but not so tight that there is a strain on the connections.

Recommended Fuses, Breakers, and Wire Sizes for Inverters
Inverter Watts Inverter DC voltage Input Fuse/Breaker DC Wire Size
Minimum !
50-150 12 20 amp 12 to 14
200-250 12 30-40 amp 8 to 10
300-500 12 50-60 amp 6 to 8
600-1000 12 110 amp 4 to 6
1100-1500 12 200 amp/175 bkr 2/0 to 2
1100-1500 24 110 amp 2/0 to 4
1800-2500 12 300 to 400 amp/250 4/0
1800-2500 24 200 amp/175 2/0
2600-3600 24 400 amp/250 4/0
4000 24 400 amp/250 4/0
4000 48 200 amp/175 2/0
5500 48 200 amp/175 2/0

These are the recommended cable sizes for a ten-foot distance from the batteries to the inverter. Note that the larger wire size is the recommended, the smaller wire size is the absolute minimum for safe operation. The sizes recommended are from a combination of maximum wire amperage capacity and voltage drop. You can't go wrong using bigger wire.

The fuse and breaker sizes shown are approximate. Since transformer based (Outback Power, Xantrex) inverters usually have a much higher maximum surge rating than electronic based (Samlex, Exeltech, Statpower), they should always use the larger if more than one size is shown. The reason some show a smaller breaker size than fuse size is that breakers do not blow as fast on a temporary surge.

The fuse should NEVER be bigger than 125% of the maximum surge power of the inverter. For example, an inverter is rated at 1000 watts, and 1800 watts surge. For a 12 volt inverter, divide 1800 by 12, which gives you 150. 150 x 1.25 = 190 amp. The nearest standard size fuse is 200 amp. You are always safe going to a smaller fuse, but if too small it might blow on heavy loads. DC breakers should be rated for about the maximum amperage draw, as they have a slight time delay on over current.

Which inverter has the best sine wave?
In general, from best down, it is Exeltech, Outback Power, Statpower, Samlex. All are good enough for 99% of all applications, but the Exeltech may be better for low power critical applications, such as recording or studio vans, or noise sensitive medical equipment. For higher power systems that need the best sine wave, either the Outback Power series or the Xantrex SW+ series.

Which is the "best" inverter?
There is no "best" for all purposes. Although the Outback Power & Xantrex are considered by many to be the top of the line, it does not make sense to spend $500 to $3000 when all you need is a little Statpower Prowatt or Exeltech 125 watt sine wave to power up a laptop. The best way to decide on what inverter is best is to work backwards - figure out what you are going to use it for, and then find one that fits those requirements. Also, some inverters have built in chargers, which may be needed in some systems. The Outback & Xantrex sine wave units include software and hardware for remote generator start, alarms, remote control and monitoring, computer data, and other functions - in many applications this is very important. If you are running pumps or other large motors, Xantrex or Outback are the only one we will recommend, even though some others might work.