How to make an Inverter- Simple 40 Watt Inverter

How to make an Inverter


This is the schematic of a simple 40W , 12 volts to 220 Volts inverter.You don’t believe, this is simple and cheap and working for me for last 4 years.The heart of the circuit is a CD 4047 IC which is wired as an astable multi vibrator here.Resistance and Capacitance at pin 1&2 determines the out put frequency.Here it is set to 60Hz.Due to this a two 180 degree out of phase ,120 Hz , 50% duty cycle waveforms will appear at pin 10 & 11.These waves are amplified by the complementary symmetry amplifier made of transistors BC 337 & TIP 3055 to drive the out put transformer.Don’t get feared of the technical terms, just wire it on a all purpose PCB.It is simple and will work.Don’t worry about the transformer windings ,buy a 220-110-0 primary,12-0-12 secondary , <50W transformer.You can select output voltage of 110V or 220V by a two way switch using such a transformer.Don’t worry if you don’t have such a transformer, a simple 220 to 12-0-12 will also do the trick sacrificing the 110V option or vice versa.The best way to get a transformer is to break all useless electronic devices in your trash.Most probably you will find the transformer or more components needed here!

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Simple Inverter Circuit Diagram:

simple inverter circuit

Simple Inverter circuit

Tips :

First wire to oscillator part only.Then check out put Pin 10 &11 of CD4047 to obtain the required wave forms ( two 120Hz ,180 degree out of phase,50% duty cycle waves.

Then connect transistors ,transformer and load (25 W bulb for test).See it working!.

We have more Inverter circuits which may interest you:

1. Simple 100 Watt Inverter Circuit

2. 60 Watt Inverter using Transistors

3. 100 Watt Inverter Circuit – using 2N3055

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66 thoughts on “How to make an Inverter- Simple 40 Watt Inverter

  1. ashok

    can i use 6A 12 v battery instead of 2-4A 12 volt if yes what i have to replace or add in the circuit

  2. shailandra

    Hello sir, i want to know that which type of transformer we can use in it. Please reply me very soon with detailed description of it.

    Thanking you,


  3. Prashant

    Hello sir, I want to make circuit of led bulb works on 240 v ac. With high brightness for house use so,please help me for construction.

  4. hamza

    hello sir i have a problem during designing this circuit that ic you have used is not in the softwares can you tell another equivalent ic number which can perform the same task
    reply as soon as poosible
    thankng u

  5. Nitin

    Dear sir, I have one UPS normally used for backup for PC or LAPTOP for about 15 min. Please tell me what is power output of the UPS and can i increase the backup time. Thanking you

    • Seetharaman

      Normally they are 250 VA type, using a 12 volts 7 AH battery of C20 rating. That is you can draw 350mA for 20 Hours. That is 4.2 watts for 20 hours. That does not mean that you can draw 42 watts for 2 hours and 336 watts for 15 minutes. As you draw higher current the battery rating will come down drastically. If you draw around 200 watts it will work for 15 minutes with a fully charged fresh battery. 15 minutes is more than sufficient to save the work and shut down the computer. For longer duration operation you have use external higher AH rated battery provided the electronics in the UPS can take care of the longer duration of operation at higher VA rating. You have to us external charger for the battery as the UPS can take care of only 7 AH battery.

  6. daniel omoha

    I love your work. I am a college student in nigeria,I will like to have more details about Inverter. circuit. thank you

    • Seetharaman

      Hi CD4047 is the oscillator with two 180 deg phase difference output this is fed to a push pull power driver transistor pair BC337 & 2N3055. which in turn drives the primary 12 volt winding of the inverter transformer, which is a step up transformer its output is available as 100 volt or 220 volt at 60Hz square wave.

  7. Abubakar ibrahim

    Good work sir, please sir i need a high frequency inverter circuit so that it can drive a tiny ferrite transformer. Thank u sir

      • Jon

        Are you sure it’s a sine wave output? Doubt it, 4047 IC outputs pulse square wave.. do you have any proof or tried already this circuit output on an oscilloscope? I think it’s just a square wave not even a modified sine wave.

  8. Taimur

    Sir I don’t have oscilloscope or frequency meter etc to make sure Im having two 120Hz out of phase waves
    All this circuit told by you is perfect right? So may i just make it like the way you have drawn without any modifications or assurance to check the output wave?

  9. Omega9850

    Just a little heads up… This circuit is good, but may cause some confusion.

    The ZENER DIODE that is rated 10 VOLTS and .5 VOLTS is actually a 10 VOLT 5 WATT Zener Diode.

    All RESISTORS should be 1/2 Watt 5-10% Tolerance.

    All CAPACITORS should be Ceramic and 20+ Volts.

    All TRANSISTORS should have HEATSINKS!

    The Amp rating of the BATTERY, FUSE, and TRANSFORMER must match up! (A regulator can be used to regulate the battery power).

    By following the schematics and these instructions, you should be able to build a good Inverter. Remember, 120 Volts is a lot, and at 40 Watts is well beyond lethal. Electrolytic Capacitors will be OK, but Ceramics are recommended as they have a longer lifespan.

  10. miloman

    Hallo, this be very good circuit, can you please tell me, I have many many wall wart transformers and my old power supply transformers, but not one center tap in thee whole mess. Short of stripping a core and re-winding, I read somewhere way back when, that two Identical transformers can be joined in such a way as to produce a centerTap, but that the polarity “-, +” on each trans should be Identified, and then hooked up,,,WHICH way? I cannot remember? Thanks so muchous for this circue,

  11. mathew

    hi i had gone throug your site and itwas excellent,i saw how to make an inerter,please can u send circuit diagram to convert 20volts into watta. please help me ok, from nigeria

  12. Kiran

    i had gone through your site and it was excellent. i saw how to make an inverter . can u please send a circuit diagram to convert 6 volts into 40 watts. Please send it as soon as possible.

    frm kiran.

  13. Rithwik

    Donot use a 9-0-9 transformer,the output voltage will be very high.use 12-0-12.You can believe me because i made is working in good condition.use a medium sized heat sink for transistor.I lost one transistor because its sink was loose.its very cheap except for the 5A transformer.

  14. Biswas

    Hi, i want to make 60watt inverter. And i have an transformer, can i use 12-0-12v to 230v 5A Transformer instead of 9-0-9v to 230v 5A. if yes what changes should i make to the circuit.

  15. Pravin B.


    It really works.

    But I want to built an inverter having variable frequency 100-to-10K Hz. Will you pls give me calculations for the same.

  16. Seetharaman

    IRF250 or its equivallent can be used directly in this same circuit. Standard 10-0-10volt inverter transformers can be used. If freewheeling diodes are not built-in in the IRF use IN5404 parellel in reverse biased with IRF.

  17. Haseeb Haider

    thats nice
    but i want the output voltage to be 12 v
    i think removal of transformer would do that ? ?
    what do u say ?
    how much amperes would it give in case of 12 v ?
    i want to use it with a 12v dry battery for my network router + switch


    HI please help me i have made the circuit for the model making competition but the problems is simple IT isnt working when i connect the circuit it draws 1.1A please sombody help meeee thanks in advance

  19. jhong

    i just used a 3055 npn Q ,,,and a 470 .180, and capacitor,,,,,,,,,and a core of am antenna………in the output,,,but it works,,,,,

  20. Kamran S

    Hi, how can I clean up the output of an off the shelf 12VDC-120VAC inverter, with “Modified Sine WAve” output, so that I can operate an SCR type dimmer with it?

  21. nick

    Thanks for the simple and easy inverter design, please can u help me to upgrade the circuit to 2000 watts ? , i know that more transistors and a bigger transformer should be added and that the power source should be no less than 48 volts DC , but i don’t know how to put everything together.

    Thanks a lot


  22. VIRAJ

    hey this is great circuit.. it works ..
    could you show me a circuit where i can work with 9 volts dry cell instead of 12 volts.

    Reply:Dry cells dont work good with inverters.It is always good to use lead acid batteries.If you are planning to use a 9V battery then use a 9-0-9 / 0-110-220 V transformer as TRA


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