100w Inverter circuit 12V to 220V using Transistor

You can read books at night under a light. Energy from AC main makes it happen. But if you do not have an AC voltage. Do You still use a light? You need to use a 100w Inverter circuit and battery. Also, If you are outside a house, no electricity. You cannot use a lamp with a 12V battery.

This circuit is a mini inverter circuit using power transistor 2N3055 as the main component without IC.

100w Inverter circuit 12V to 220V using Transistor

It is designed for you that need to use appliances outdoor or no electricity.  Someone use it in a car or the high mountain etc.

It can be converted 12VDC to 220VAC.  The maximum output power about 100 watts.  It is suitable for normal lighting (all home lamps), also used for radio, LCD TV, Stereo.

Someone uses it for a small soldering iron to repair or build many projects outdoor home.

How 100W inverter circuit works

See the circuit diagram below

100 watts inverter circuit 12v-to-220v using transistors

Figure 1,  100w Inverter circuit, 12V to 220VAC using transistors

This circuit will include five main sections as a block diagram.

100w inverter block diagram

1. Q1 and  Q2 act as the frequency oscillator circuit.
2. Q3 and Q4 act as the frequency divider circuit
3. Q5 and Q6 act as the transistor driver circuit.
4. Q7 and Q8 act as the output power amplifier circuit.
5. T1 is a voltage converter to power a load.

Here is a step-by-step process.

First,  both PNP transistors Q1, Q2 will be connected together as the astable multivibrator form. They will generate the output frequency of about 100 Hz at the collector lead of Q2.

This frequency is set by both resistors R1, R2, and two capacitors C1, C2. And there are both diodes D1, D2 to set only positive voltage through the emitter lead of Q1, Q2.

Then, this signal flows through to the frequency divider by two. It makes the frequency is reduced down to about 50Hz.

Why designer does not set the circuit to directly work at 50 Hz. Because generating the steady low frequency is too hard.

This frequency has value the same as the AC main.

It will be a waveform of low-power alternating current. And, out to the collector leads of transistors Q3, Q4. Then, via resistors R8, R9, and R11, R12.

They are a voltage divider circuit to biased for driver transistors Q5 and Q6. To drive the power transistors Q7, Q8 alternately power the high current to the inductance coil in the transformer T1. It will induce electrical energy through the metal core from a set of 12V coils to an AC voltage of 220V at 50Hz to 60Hz for further use.


1. Normally, use the 2-3A transformers for 20 watts to 30watts for light bulbs. But you want 100 watts, you must use an 8A transformer. It is so expensive for me.

2. The primary coil of a transformer, you may use 9V CT 9V or 10V CT 10V or 12V CT 12V.

If you use a 9V CT 9V transformer. The output voltage will be 250V (approx).

Which normal I use 12V CT 12V, makes the output voltage about AC 220V (no-load). But with load, the voltage will reduce to AC 190V

3.This circuit will have output as a square waveform. So cannot use for inductor load.

But it’s enough for mini electrical appliances. Such as electric soldering iron, Digital TV, Mobile Charger, Small laptop, etc.

4. This transformer, we may use a secondary coil as the output voltage as you need. The example we connect to the power amplifier that uses AC 24 volts. So we use AC 24V secondary coil, etc.

How to builds

Similar to the various projects that have passed. To begin with, make the PCB or you can use the universal PCB(Perforated PCB). Then, assemble all parts on PCB as Fig. Next check all for errors. Check again and check again.

Then, apply the 12V 10A battery to this circuit. And use the voltmeter to measure AC voltage output. Next, connects the load to the circuit. is it easy?

100W transistor inverter PCB layout

PCB layout

Components layout 100w transistor inverter

Components layout

PCB layout and components layouts of the 100w Inverter circuit, 12V to 220V using Transistors

Parts you will need

Q1-Q4: BC557, 45V 100mA PNP Transistor
Q5, Q6: BD139, 80V 1.5A NPN Transistor
Q7, Q8: 2N3055, 100V, 15A, 115W, >2,5MHz NPN transistor
D1, D2, D3, D4: 1N4148, 75V 150mA Diodes
D5, D6: 1N4007, 1000V 1A Diodes

0.5W Resistors tolerance: 5%
R1, R4, R6, R7: 10K
R2, R3: 150K
R5, R6: 47K
R9, R12: 220 ohms
R10, R13: 560 ohms
R11, R14: 100K
R17, R18: 150 ohms
R15, R16: 10 ohms, 10W Resistors tolerance: 5%

Ceramic capacitors
C1,C2: 0.047uF 50V
C3,C4: 0.01uF 50V
C5: 1uF 50V
C6: 0.1uF 250VAC
C7: 0.1uF 50V
C8: 220uF 25V, Electrolytic capacitors
T1: 220V/120V AC primary to 12V-0-12V,2-8A secondary transformer.

Be careful connecting components

Are components backward? You must connect them in proper pins only. Look at connecting correctly capacitors, Diodes, Diodes, transistors, etc.

Must connect them correctly

For 2N3055 transistors, look at mounting it on the heatsink.

Proper way mounting 2N3055 in heatsink

The screws should be tightened. Because a large amount of current flows through Pin C to Pin E.

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83 thoughts on “100w Inverter circuit 12V to 220V using Transistor”

  1. i try to build this inverter but did not work. the one transistor 2n3055 is hot. please any body help me to work this circuit.

  2. i have done everything but is not working. When i connect the power (battery 12v) is not giving any output at all.And am worry bcos that is my project and am working on it but still is not working so i want u to help me

    FOR A 500 WATT INVERTER—-12VDC—-220V AC?

  4. i want to know the components i can use to build a 12v 7Ah 220v inverter 50w.please the ratings of resistors …not more than two transistor

  5. which type of transformer you used is this a current transformer or simple center tapped transformer plz help me I want to build this circuit

  6. thank you sir, it is agood idea.ihave worked it out for two years but still working.even i have improved it to 500W and beyond. God bless you.

  7. Plz give how many ampr is required at input side in 12v dc battery?
    12v dc but amp_?
    and also tell me about the transformer rating, voltage_ and amp_?

  8. Hello
    Site is very useful
    I love some of the questions LaSalle
    I would love to Create symbol such as this therefore sent this letter to you this Model
    Micro Inverter using TIP41 or 2N6121 Eleccircuit_com.mht
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    But I’ve found a wire size of 20 within the components and district did not understand his place in the circle
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    I hope for your reply and help me
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  9. hi 4 all
    momename thannks
    Thanks so much for the founder of the site, which allowed us to posts and thanks also to his esteemed visitors
    Ask the electronic circuit for xenon used in lighting the front of the car and gives a strong white light searched the forums English and found them talking about circles xenon flash any light intermittent and disco parties please help me with knives circles components electronic large-sized conventional and not system components printed and does not Electronics Small Size
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  10. hi

    This line did not understand it the last line in the electronic components to build this circuit easy inverter

    solid Wires no. 20 AWG length 1 feet, for what iam not understand is it for main connector or???please help me

    [email protected]

  11. mome.name

    What is the reason that in the absence of even one letter omitted patient Xue

    ما سبب الغياب ما في حتى رساله واحده بيها اصبر شويه ما الوعد بيناتنا الفه اغنيه سودانيه مهداه لحصرتك

  12. mome.name

    What is the reason that in the absence of even one letter omitted patient Xue

    المهندس الغالي
    ان كنت تتكلم العربيع يجب ان نتخاطب بالعربيه في رسائلنا القادمات واشكر رحابة وسعة صدرك وكرمك الفياض

    ما سبب الغياب ما في حتى رساله واحده بيها اصبر شويه ما الوعد بيناتنا الفه اغنيه سودانيه مهداه لحصرتك

  13. sir!
    i want to apply this idea in my final year project please send me more detail about Inverter 12V to 220V 100W by Transistor.
    i want to submit proposal on this topic for my final year project

  14. I want to apply this idea in my final year project please send me more detail like abstract and applications about Inverter 12V to 220V 100W by Transistor.

  15. I don’t have transistor BC139 and resistor 10ohm 10 watt what other transistor and resistor can I use instead of that transistor and resistor ?

  16. sir im getting 12v at input side of transformer before conectng transformer… bt wen i connect transformer voltage become 6v and im getting nly 110v output from transformer. please help me. im using 12-0-12 to 230v ,3amp transformer.

  17. The mistake was mine.There were error in connections.But another problem now is i cant simulate it in protus with some load connected to it.
    can someone help please

  18. I just wanna design a 1000watts pure sine wave inverter can u assist me knw the suitable ratings of the transform I am to use in my design otherwise assist me

  19. All about was good but I need a 100 watt output inverter to use as input power for operate a 1000watt inverter with full load. Give me a giagram for the same.

  20. Hi friends
    I have one doubt about inverter. Many of circuits are available via net but lot of circuits output power is not given. So my question is how to calculate output power of inverter.

  21. I am trying connect the circuit in PCB what am supposed to use for the transformer and center tap and how can I connect it will be help full if you guide me as soon as possible . If you build this circuit in pspice that will be great .
    -thank you.

  22. One 10 ohm resistor is getting hot but another one is not. Frequency divider circuit’s 2 output’s are different voltages. I checked my connection and element’s values. There is no error. Then I don’t understand what’s wrong. Reply please

  23. when i connect 12 volts to circuit . battery voltage decreasing to 6v and output is 6v-0-6v.plz help me.remaining things are perfect

  24. sir…its so need to know me….is this possible 6volt dc to 12 volt dc..inverter?. please if you tell me and give me the diagram….I want make it…

  25. Hai, can u please give me a solution for my question it is that how to produce 7amps current as an output by giving dc voltage as an input to the circuit , one important thing is that without using transformer please help me guys.


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