60W inverter using transistors

john September 18, 2009 77 Comments

Here is the circuit diagram of a fully transistorized inverter that can drive up to 60W loads. Transistors Q1 and Q2 forms a 50Hz astable multivibrator. The output from the collector of Q2 is connected to the input of the Darlington pair formed by Q3 and Q4.Similarly the output of Q1 is coupled to the input of the pair Q5 and Q6. The output from the Darlington pairs drive the final output transistors Q7 and Q8 which are wired in the push pull configuration to drive the output transformer.
Circuit diagram.

60W inverter using transitors


  • The circuit can be assembled on a vero board.
  • T1 can be a 230V primary to 9-0-9V, 6A secondary transformer.
  • Transistors Q4, Q6, Q7 and Q8 must be fitted with heat sinks.
  • Use a 12V, 7Ah battery for powering the inverter.
  • Slight adjustments can be made on the value of R3 and R4 to get exact 50Hz output.

  • Premdeepak P A
    December 12, 2017

    Res Sir
    I want to make this circuit, Only question is whether I can use a 9-0-9 1 A or 2 Amps transformer and how would it differ from the output point of view

  • abrar tabbasum
    April 8, 2015


  • priya
    March 26, 2015

    how long the bulb will glow without any source?and how much time it will take to charge?

  • saiii
    February 13, 2015

    what is the transistor used in this circuit

  • sahil
    November 6, 2014

    what is application of 6ow inverter using transistors?

  • September 22, 2014

    What components are used in 60w inverter

  • September 14, 2014

    sir am getting only 130v o/p so I can not glow the 40w bulb, help me to increse my o/p voltage

  • vara prasad
    September 13, 2014

    Sir am getting only 130v o/p so I can not glow the 40w bulb

  • Ahmad
    August 26, 2014

    thanks a lot.

  • Pritam
    August 15, 2014

    hi Seetharaman.. can i replace 2n3055 with TIP122 darlington pairin order to increase power.if yes what will be the o/p power.. pls reply fast

  • Terry
    June 28, 2014

    Hi Mr Seetharaman,

    I just wanna ask how much current for this ?? Is it powerful enough to turn on the table fan ?

    • Terry
      June 28, 2014

      Or maybe a household appliances like blender ?

  • vasudev
    June 8, 2014

    hi i tried this inverter,it is not so much powerful like cd4047 inverter & how can i increase the power to 120w in this inverter

    • Seetharaman
      June 9, 2014

      Hi Vasudev try using power darlington transistor capable of 20Amps continuous collector current in place of Q7 & Q8 OR use 2nos TIP142 in parallel.

      • Vara prasad
        September 14, 2014

        Hi sir am not getting 200v, can u plz tell me that how to increase my o/p voltage and current

      • September 19, 2014

        if u drive 20amps battery will dry within a hour

  • vasudev
    June 7, 2014

    can i power up my tv by this inverter ,i mean which is the best one this or cd4047 inverter

    • Seetharaman
      June 8, 2014

      What is the load requirement if is 100watts use CD4047 inverter if it is 60Watts use this inverter.

  • vasudev
    June 4, 2014

    can i add mosfets instead of transistors

  • June 4, 2014

    Inverter and solar charger technology transfer


  • LordB1
    May 31, 2014

    want to know for how long will the inverter stay up (working duration in hours)?? Thanks!

    • Seetharaman
      June 1, 2014

      With a fully charged battery will stay for 60mts(1hr) maximum, when output is connected to 60 watts load.

  • vasudev
    May 31, 2014


    • Seetharaman
      May 31, 2014

      Are TIP41Cs getting heated up. It should work provided the Q1 and Q2 are oscillating. Check your wiring. Most important things to remember in BD140’s lead out are different from other transistors. As you view the printed side and while leads facing downwards. Left is emitter (not base) center collector and right is Base (not emitter). Please check.

      • vasudev
        June 2, 2014

        thank you i followed u, it is now working well with tip41cs

  • sns pavan
    March 12, 2014

    what r the applications of 60w inverter

    • Seetharaman
      May 27, 2014

      Use for Soldering iron, light, shaver etc using car battery when you are away in your car. During power failure at home also you can use it for various uses.
      Hi Vasudev it can power 60 watt bulb but the efficiency of these inverters depends on transformer losses and power dissipated by final transistors. you cannot expect better than 75 to 80% efficiency. With a bad quality transformer it can be even worse <50%

  • February 27, 2014

    I love this circuit. It’s working great. Thk u vry mch…

  • Isaac
    December 31, 2013


    I don’t understand what the purpose of the two diodes (D1 & D2) is. Could you please explain. Might it be taking care of flyback from the transformer winding?
    Another question, all the circuits like this which I have seen drive either pnp transistors or a pnp darlington pair.Why not npn transistors. would it still work. Appreciate your help.

  • May 2, 2013

    plz help, i have used hcf4047, 12-0-12 xtransformer and irfz44 mosfets but no output, whats my problem

    • Seetharaman
      May 3, 2013

      Pl try the following link use mosfet in place of power darlington

    • jojo
      May 14, 2014

      I want to make a 100w inverter i am working on it from 2 months and i change 3 circuit 2 with 4047 and 1 only with transistor but the same problem occurs in all circuit my -ve supply sparks and the last transistor heated and no output plz help me any one who any better circuit send me

  • priyank jani
    April 9, 2013

    what should be the minimum rating of input dc current in ampere hour.

    • Seetharaman
      May 3, 2013

      The current requirement at rated load is 6Amps. if you want it to work for 1hr use 7AH battery if you want it to work non stop for 8 hrs use 60AH battery.

  • ramesh
    April 6, 2013

    is it necessarily 6A transformer…???
    plz give me circuit how to build up to 200watts???

  • yatheendra
    March 28, 2013

    hai sir can we use transformer of 9-0-9 1amp in this circuit.

    March 23, 2013

    what is the specification of the transformer used in this circuit?

  • January 24, 2013

    Hi seetharaman
    I have 9-0-9v 1A transformer is it ok for inverter.

  • January 1, 2013

    This 60w Inverter Circuit is Working Great.

    • Lawrence
      July 22, 2013

      Are there any modifications you did?

    • Jaisin jacob
      August 29, 2013

      Hai,i have used a 9-0-9v,2A for the circuit for 18w.but it doesnot work.plz suggest what may be the problem?waiting for the replay.

      • seetharaman
        August 30, 2013

        Ensure your transformer is rated for 9-0-9 24VA for 18watts load. what is your load inductive / resistive ?

  • November 1, 2012

    hi sir how can i upgrade this ckt into a 200watts outpot.

  • Seetharaman
    July 20, 2012

    Hi Rajib The charge controllers are available in the market for Solar charging of batteries with 200 to 250 watts capacity solar pvcs. Use them they are most suited for your requirement

  • Rajib Banerjee
    July 19, 2012

    I want a circuit that works as a duel charger(600-800 watt)Inverter AC & Solar Parallel And If possible Need Separate Circuit of Solar Charging with battery full charging sensor with auto cut and if need after solar charging battery itself can get charge form AC.Basically Add on Circuit that be integrated with existing 600-800 watt Inverter used 12v 180Ah Inverter battery.Its Need if possible solution.reply

  • YenYes
    April 13, 2012

    Hey Guys…

    I am working on an engineering project.. using this circuit… but it only provides current up to the last resistors, I don’t get any o/p when I test the transistors 2N3055. So, the transformer shows nothing. Can you please help me… it’s critical, and, am stuck!!

    Appreciate your reply very much, Thanks!!

    March 12, 2012


    March 12, 2012


  • Taimur
    March 7, 2012

    Thankyou for your reply Sir. & I have got two questions please.
    What if instead of 12V, 7Ah battery I use a 12V 12Ah/2HR battery? What would be its affect on the whole inverter?

    Secondly by using a transformer (9-0-9)V & 6A, does it mean that this transformer will be giving an output current of 6A?
    Means that if I use a transformer which has more current rating at secondary side like lets say “10A” then does it mean that this inverter would be giving 10A to the load?

  • Seetharaman
    March 6, 2012

    The capacitor used are 16 volt or greater ceramic / polyester / paper / polycarbonate etc. (non polar type).
    You cannot eliminate the center tap, without which, the circuit will not work. All push pull designs require center tapped transformer and they are efficient designs.

    • May 5, 2013

      man this my project, can ths circuit work properly with a 12-0-12 trnsformer?

      • Seetharaman
        May 7, 2013

        Hi ntsoso the output will be less instead 230 volts you may get around 175 to 190 volts.

        • May 10, 2013

          man i used a 555 timer what kind of the cap do i use for filtering? Hav done ths on simulation and the led lights for 1sec. Help plz my friend

  • pramod
    March 5, 2012

    without a center tap transformer will this ckt able to provide the desired output

    • John Biasutti
      November 24, 2012

      If you can not find a Centre Tap transformer use 2 off 0 – 9 V transformers connected in series with the 0 V connection between the 2 transformers.

  • pramod
    March 5, 2012

    Hai could you please tell me how to eliminate center tapping freom this circuit. i am having a 0-9v transformer.

  • jp2kumar
    March 2, 2012

    i don’t understand what type of capacitor used here and voltage value any alternate solution there? pls tell me ….

  • Seetharaman
    February 22, 2012

    Hi Madhavan buy a step down transformer rated with primary 230 volt AC & secondary 9-0-9 AC rated for 6 amps. use the primary as secondary and secondary as primary.
    Hi Taimur for using with frequency sensitive devices, like line sychronised equipment etc, you have to adjust for the required frequency of the inverter, else they may mall function.

  • mathavan
    February 21, 2012


  • Taimur
    February 18, 2012

    Its mentioned here that by making slight adjustments of the resistors: we’ll be able to obtain an exact 50Hz output.. . What if i don’t make those adjustments, will i still get the appropriate output for my load(like bulb,charger or anything else etc)?

  • Avinash
    December 17, 2011

    Plz send this image in .jpg format plz plz

  • kenneth
    November 10, 2011

    Please i need a 60VA sine wave inverter circuit. 12vdc to 220vac….. how can i obtain sine wave outputs with this circuit.

  • seetharaman
    October 30, 2011

    Hi Ali the capacitors can be 16 volts or higher.

  • October 30, 2011


    I found inverter circuit very useful.
    1-in the notes ,voltage operation of capacitores
    is not mentioned.
    2- application of inverter for solr cells and bipv systems
    it is better to have more practical information

  • Shelly Jardin
    July 25, 2011

    I have done this circuit also as a project but it only provides current up to the last resistors, I don’t get anything from there when I test the transistors 2N3055 they put out nothing. Thus the transformer also shows nothing. Is there something not included here that I need to ad? Thank you

  • seetharaman
    July 17, 2011

    No it is square wave.

  • July 16, 2011

    out put this circuit sinewave or not?

  • Seetharaman
    February 27, 2011
  • umer
    February 26, 2011

    i want to design a 100 watt inverter using PWM technique
    if ny 1 have the circuit diagram so plz send it to me

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