12v to 230v Inverter Circuit Schematic using Pulse Width Modulator IC SG3525

So far we have published so many inverter circuits here at circuitsgallery and now I think it’s time for me to introduce another one that has more inverter efficiency.

By using the principle of dc to ac conversion, an inverter system helps to prevent the problem of power failure in homes, offices etc. As the system convert dc to ac, it has got the name inverter.

This is a SG3525 based inverter schematic. Here we are mainly using the internal oscillator of PWM SG3525.

Note: You can buy this 12vDC to 120vAC inverter from our online store.

IC SG3525 is a pulse width modulator integrated circuit which has the following features:

  • Wide operating voltage range from 8 to 35V
  • Inbuilt oscillator and frequency range 100HZ to 500KHz
  • Input and output synchronization terminals
  • Variable dead time controller
  • Soft-start facility
  • Smooth shut down facility
  • Input voltage checking facility
  • Dual source/sink output driver

Recommended for you:

Single phase inverter circuit diagram

SG3525 PWM inverter circuit

Components Required

  1. IC SG3525
  2. MOFFETS IRF Z44 x2
  3. Resistors (22,10K,56K,12K,470,33×2,)
  4. Resistors(220×4 ½ watt)
  5. Capacitor (0.01uFx3, 1000uF/25V ,2.2uF/25V ,1K100,102K, 47uF/25Vx2)
  6. Transformer 12-012V /5A step down transformer(we use as inverted)

Working of 100 watt inverter circuit diagram

  • SG3525 has an inbuilt oscillator whose frequency can be determined by connecting capacitor and resistor on pin 5 and pin 6 respectively.
  • The frequency of oscillation can be calculated by the equation

frequency equation sg3525

  • Output is taken from pins 11 and 14 which are connected to the gates of Mosfets.
  • Pins 11 and 14 operate as totem pole configuration or a push pull manner. It never turns ON two pins at the same time.
  • The signal from two pins 11 and 14 are connected to the gates of power mosfets IRF Z44 which switch current to each winding of the transformer.
  • Only one winding is activated at a time and both are energized in opposite directions.
  • Activation of winding in opposite direction helps to produce an alternating EMF and thus alternating current (AC) on the secondary of the transformer.
  • The frequency of the output AC is 50Hz which is determined by the CT and RT pins of SG3525(pin 5 and 6).

Components Pin out

SG3525 pwm pin out     IRFZ44 Power mosfet pin out

76 thoughts on “12v to 230v Inverter Circuit Schematic using Pulse Width Modulator IC SG3525

  1. In first Happy New Year !!!
    Compliment for this very interesting site.
    Reading this article I have found this:
    “Note: You can buy this 12vDC to 120vAC inverter from our online store.”
    Where is the link of.

    Best Regards.

      • hi, it’s my first time build an Inverter neh, thing is, The circuit diagram of The pwm, doesn’t seem to make sense as it shows The ic with all sided pins while The one at The bottom and The one I bought is two sided and also, it doesn’t say as to The porality of The ic or where The lines to The mosfets come from. could you please grant me some clarity and if possibles, email me a more detailed diagram.

        am gonna be using The circuit system to drive a Brushless motor which I reckon it will work. besides, I have alert bought all The components. please, I need it like yesterday already.
        thanks and God bless

    • It’s possible by varying the frequency of oscillation specified in the working(see the equation), but you won’t be able to use it with common electric appliances as they operate on 50/60 Hz only.

    • Hey Mahaveer,
      Yes, you can increase output power by replacing transformer and increasing the number Mosfets (connect in parallel).

      • hi,

        am designing dc to ac converter my output spec is 110v,400hz . as per formula u gave. if i apply values u tken in that formula am getting 20hz instead of 50hz. RT=68K,CT=1UF,RD=470 with these values am getting 20hz.
        can you please help me in designing 400hz,110v inverter
        waiting for the reply


  2. What may happen if I increase the number of FETs in parallel and don’t change the transfomer? Do FETs IRFP50N06 work well for a high power inverter using the above driver circuit because am done wiz its assembly? Thanks

  3. Sir, I made an inverter one time using a two transistor astable multivibrator but it seems its power or current output is very weak because if connect a hair shaving clipper; it operates very weakly indicating either low voltage or power bt the transformer is big enough because I got it from a 1.5KVA AC voltage regulator and I altered i to a normal centre-tapped transfomer. And if I measure t output when on No load I get 250V AC output; I don’t know what may be the cause just help me.Thanks

  4. Hai…. very nice circuit…. Plz let me know whether i can connect any sophisticated devices like laptops at the inverter output ?
    Also how could i regulate the output voltage of this inverter to make independent of load variations ?

    Expecting a good reply soon

  5. hi,

    am designing dc to ac converter my output spec is 110v,400hz . as per formula u gave. if i apply values u tken in that formula am getting 20hz instead of 50hz. RT=68K,CT=1UF,RD=470 with these values am getting 20hz.
    can you please help me in designing 400hz,110v inverter
    waiting for the reply


    • First I made the same circuit by the same values as he described above. But the output was having some problems, it was flickering. Then I changed the value of Rt from 68k to 56k, now it was working fine.

      If you got the frequency by calculating by the values, then why don’t you try some other values for that.

  6. it can be possible that i can redesign this circuit?..become 6v dc to 220v ac, 100 watt?..can you help me to design this can of inverter circuit?

  7. Can I use IRFZ640 instead IRFZ44? last time is use IRFZ640 in your given circuit with NE555 it didn’t work.
    kindly tell me more No.s of mos fete that we can use in this inverter instead of IRFZ44 please. . . .

  8. HI. I am trying to simulate this circuit on proteus but it is not working. The mosfets give no output even though the output pins are.

  9. sir i have made this circuit but it doesn’t work i checked connections properly but still not work any o/p so plz give me solution

    • Please recheck the circuit, because I tried the same circuit and it’s working fine.
      Recheck the pins of IC capacitor and resistor specially the Mosfet Pins, because if the pins are not correct it won’t work. For IRFZ44n the pins are 1- Gate 2- Drain 3- Source

  10. hi Sir,

    can i use only one mosfet to vary pulse.Like output pin14 is not connecting to mosfet.But output of pin11 is giving to gate of other mosfet,drain is going to primary of transformer and source is grounding.is there possible to connect like this or not???pls ans…

    • No. If you want to work this circuit diagram properly you must have to connect the two output pins to the Mosfet gates. Because the two sides of the transformer winding’s need to get the ground supply through the Mosfets

  11. how to change output voltage magnitude…………………why use resistor and capacitor parallel to the mosfet…………..any possible to connect this inverter to the grid

  12. Hi Sir,
    I want to put 4 irfz44 in my inverter ,can you tell how to do it?
    What kind of capacitor are 1k100 and 102k ?

  13. Q.
    Hello everyone can somebody help me.
    I have a problem with this inverter i am using the sg3525 .. the frecuency just staid at 60 hrz for 5 seconds after that jump to 135 and like 10 seconds later to 385 .. how can it staid at 60hrz.

    1. 1
    —————————– — ————————-
    0.7*112k+3( 1000 )*200nf. 78400+3000*0.0000002

    Thank ‘s.

  14. Can you advice me if how many IRF Z44s I need to have a 1000W output? and what is the rating of the transformer do I need? Do I have to change the wattage ratings of the resistors, how about the capacitors?….Is it possible to have a pure sine wave output? Thanks

  15. Thanks for posting – I need a 12vDC to 110VAC inverter rated at ~100W, so this design is perfect.
    The only question is where to buy a suitable transformer? What does 12-0-12 refer to?

  16. I have built the circuit but the output is flicking … Can you guide on this .. Values of all the components is checked . hey are correct.

  17. with mosfet IRF250 connected IN parallel to make upto 2KVA inverter with 2KVA transformer, can this circuit carry deep freezer, also A.C and if increase to 5KVA as 24v inverter (input) can it power washing machine and pumping machine, thanks FRom Blessing…

  18. hello there,
    in this ckt dc battery connected is of 12 volt, what is its current rating ? i mean ( for example ) if u r designing 220W inverter and output voltage is 220 volt then current must be 1 amp. so, what should be the current requirement from dc battery connected ? in general input power and output power are always same but because of losses input power should be little higher than output power. so if we r designing 100W inverter then input power must also be 100W, means 12V,8.5 A dc.
    what is current rating in your given ckt.

  19. sir, if I use power amplification using like 10mosphet ,will there be an increase in my watt…. and if yes like how many watt can I derive?

  20. how do we calculate the value of the resistances and capacitance used ?
    plz reply
    my specifications of inverter: 50 Hz ,transformer ;12-0-12 v to 230 v ac ,1A current rating.
    plz help.

  21. Hello. Is there any feedback control. ? How to make it’s output voltage exact 220 V ac ?
    Please reply.

  22. Sir by increasing the mosfet in parallel can I still increase the resistor and capacitor connected to the source and gate

  23. hai guys

    i made tl 494 inverter cct.but it wont work perfectlly .it waste lot of my money for mosfets and ic s . when paralling two mosfet suddnly get burnt.
    does eny one try this circuit with two or three mosfets in parallel.
    please reply
    will it work fine

  24. Sir whatt is the output of this diagram in waveforms we want to see wave forms…..????can you show us….

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