How to make an Inverter- Simple 40 Watt Inverter

jacky October 17, 2018 71 Comments

In this project, let’s learn how to make an Inverter – a Simple 40 watts inverter circuit using minimal components. An inverter circuit is often used in DC to AC applications and is a necessary in many electronics applications. The heart of this circuit is digital IC CD4047 – which is a very popular component.

Let’s Build our Simple 40 Watt 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

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

  • zeeshan
    June 26, 2018

    sir i need 20 watt inverter. can u send me diagrame of this circuit. and its components?

  • abdulgafar ibrahim
    July 20, 2017

    pls can i find the video of this in…….

  • takis kalas
    May 23, 2017

    Hallo , your blueprint is good! I have a power supply at 50 Hz and by the use of this inverting circuit i want to produce an 120 volt at 60Hz. I connected the Capacitor and the resistors between legs 1,2,3 as shown. Firstly i should not care for the capacitors polarity on pins 1,3 ? Secondly i can not adjust the frequency of the produced signal . I always get 50 Hz. How can i change this? Is only the resistors and capacitor involved on produced signals frequency? Thank you in advance.

  • Makinwa Christopher
    February 27, 2017

    Sir. pls i need your help on a personal project of mine in making an inverter. i will so much love it if we can communicate through the mail to reduce stress. Love your work keep it up pls

  • March 28, 2016

    this is not working can i use 6A 12 v battery…

  • ashok
    July 8, 2015

    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

  • October 10, 2014

    can I charge my inverter battery using the AC output of my inverter through a charger in order to ensure a continuous supply?

  • advaith p
    October 8, 2014

    sir,can i use 10 ni-mh 1.2v battery insted of 12v battery

  • advaith p
    October 8, 2014

    can i use 1.2v ni-mh battery insted of acid lead battery?
    please give me answer

  • shailandra
    September 7, 2014

    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,


    • seetharaman
      September 30, 2014

      Please read the article again it is clearly given about its rating.

  • Prashant
    August 24, 2014

    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.

    • prakash
      September 27, 2014

      u send me ur main problem regarding this in a written form on mail id,,, then i will send u material… on ur gmail….

  • May 7, 2014

    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

  • Nitin
    April 26, 2014

    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
      April 26, 2014

      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.

  • daniel omoha
    April 18, 2014

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

  • binu
    March 31, 2014

    can you please explain the design of the cicuit?

    • Seetharaman
      March 31, 2014

      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.

  • Joshua
    November 25, 2013

    How can i build a contineous motor without fuel? And pls sir i need 500watts circuit

  • Joshua
    November 25, 2013

    How can i build a contineous motor without fuel?

  • Sams ababio
    November 6, 2013

    Great job! Please sir, send me 3000 watt circuit

  • Bharathi
    September 28, 2013

    can you explain this project breifly…

  • Krismar
    September 28, 2013

    Is it ok to use a 12v battery 38 AH for this project? what is the output? is tthat 20-40Volts?

  • Abubakar ibrahim
    May 29, 2013

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

  • abel thomas
    March 13, 2013

    Thank a lot for your technical support which you give to.

  • January 16, 2013

    please can you send me a 120 watts inverter circuit diagram

  • nagalakshmi
    January 15, 2013

    need exact details about the components and accurate circuits

  • cyberpks
    July 19, 2012

    Can I use a BC547/548 in place of BC337?

    • Seetharaman
      March 16, 2013

      Hi no you can use 2N1711 or equivalent medium current and voltage switching transistor.

  • jeniffer
    May 7, 2012

    hello,,what the output waveform of this inverter??square wave??

    • billy
      December 27, 2012

      hello jennifer, it’s a sinusoidal wave.

      • Jon
        April 26, 2013

        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.

    • Seetharaman
      April 28, 2013

      Hallo Jeniffer No. it is only square wave. (people call this as digital inverter?!)

  • Pujan
    April 9, 2012

    Sir, could you tell how to measure watt

    • san
      April 7, 2013

      watt is the unit of power
      p=i^2*R or VI

  • Taimur
    March 7, 2012

    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?

  • vikram
    February 18, 2012

    is it safe to use 2x6V (4.5Ah) sla battery in series as a power supply to the inverter?

  • saddd...............!
    February 9, 2012

    can u please explain briefly…….?

  • vikram
    January 19, 2012

    And also please mention the Ah rating of the battery for long backup for an 10w cfl load…..

  • vikram
    January 19, 2012

    what type of battery do i need to use in this ckt for better power output(40W)?

  • Omega9850
    November 15, 2011

    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.

    • Lawrence
      July 22, 2013

      Very insightful, am yet to build the inverter but please comment on the other circuits as well.

  • seetharaman
    July 14, 2011

    Miloman send your enq. to i will send you the detailed circuit.

  • miloman
    July 13, 2011

    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,

  • mathew
    June 7, 2011

    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

  • Kiran
    May 17, 2011

    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.

  • Rithwik
    January 28, 2011

    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.

    • May 20, 2013

      did you wire this circuit the i see it here or is there anything you did? Plz help me man

  • Negin
    January 7, 2011

    replace R and C

  • Negin
    January 7, 2011

    The formula for calculating the frequency is: f=1/(4.4RC)
    R: between pins 1 and 3
    C: between pins 2 and 3

  • November 1, 2010

    Can u plz send me a perfect 150-250watt inverter circuit diagram (pure 50hz).

  • November 1, 2010

    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.

    • dilnawaz
      October 4, 2015

      Sir can i use transformar 12-012v 800

    October 20, 2010

    Pls can i get a circuite diagram of a 2,500watt inveter & d names of all it component .Thanks

  • Pravin B.
    June 15, 2010


    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.

  • Seetharaman
    December 23, 2009

    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.

  • Haseeb Haider
    December 19, 2009

    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

    December 18, 2009

    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

  • jhong
    December 5, 2009

    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,,,,,

  • abdul
    September 14, 2009

    what will be the value of resistor and capacitor at pin 1 & 2 to get 50hz and 220v.

  • Kamran S
    August 17, 2009

    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?

  • Jasveer
    February 28, 2009

    its a simple and easy inverter design, please can u help me to design a circuit of 2.5k watts ?

    Thanks a lot

  • nick
    January 13, 2009

    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


  • Sty
    November 8, 2008

    Instead of Bipolar TIP3055, is there any way to use MOSFET such as IRF?

    October 10, 2008

    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

  • September 15, 2008


  • June 19, 2008

    Use a 9-0-9V transformer, NOT 12-0-12 as shown.
    Output voltage will be low otherwise.

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