Make Simple 555 Inverter circuit using MOSFET

Do you want to know more about this simple inverter circuit? Capable of outputting 50 watts total with just a few components.

This is an IC 555 inverter circuit. Because of using the 555 TIMER and MOSFET as main. I experiment with it to work well.

555 Inverter circuit using MOSFET

When using a 12V battery as a source, it will output 220V AC 50Hz

The Basic Principle of the Circuit

We think most people do not like reading a long yet tedious explanation. So to keep it simple, we recommend: simple principle inverter

inverter working principle

Initially, the DC voltage from the battery goes into a square wave oscillator circuit (50Hz Oscillator), producing 50Hz AC voltage. But the current is way too low.

Recommended: How does NE555 timer circuit work

What to do to raise the current?

In this case, power switching (A-B switch) such as power transistors or MOSFETs are one good choice.

But the AC voltage is still at 12V? The Transformer inductance will raise the voltage into
220V AC 50Hz, ready to be applied to a load.

How 555 inverter circuit works

The circuit below is a complete circuit diagram of this project. I use the IC-NE555 timer is a square wave frequency generator output of 50Hz.

555 inverter circuit diagram with MOSFET

The frequency is determined by the R2 Resistor and C1 Capacitor.

555’s Output Frequency Calculation

If your R2 is 150K, then the output is 47Hz. You may add a potentiometer to fine-tune it to 50Hz later down the line.

MF4Me said: By calculation (results will vary depending on the component tolerances) a good combo of common parts would be:

  • 0.2 μF (2 x 0.1 in parallel)
  • 100Ω for R1
  • 72K (39K and 33K in series) for R2.

Calculation of 50HZ frequency of 555

The calculation result is 50.069 Hz with a 50.03 duty cycle. That is smart accuracy. If its tolerances are low.

What is more?

We use N-type MOSFET IRF540 (Q2, Q3) to drive a transformer coil (primary winding).

The output current at Pin 3 of IC1 will flow in two ways.

  • First, through R3 to a gate of Q2.
  • Second, flows to Q1-transistor BC549 as inverter logic form to reverse signal difference first ways.

Next, the current flows to the gate of Q3 to also drive the transformer. 

It inducted low voltage to high voltage, from about 220V to 250V depending on the battery (12V to 14.4V).

The circuit diagram of the MOSFET Inverter

For the transformer, I use 2A of current, if a 12V input voltage. It causes the output power to be more than 100 watts.

Here are a few related posts you may find helpful, too:

Why use MOSFET?

In the circuit, we use IRF540 MOSFET. There are many reasons to use them.

  1.  It is easy to use.  They do not need the pre-drive transistor in Darlington to be the same as normal transistors, such as TIP41, 2SC1061, etc.
  2. It can drive a high current load, 27A max. While the TIP41 transistor can only drive a 4A load.
  3. It is inexpensive, just 0.8USD per pc.
  4. The body is similar to a TIP41 transistor, so it is easy to mount to a heatsink.
  5. They can be mounted to a smaller heatsink than a transistor, because of their low heat output.

The component list

IC1: NE555 timer IC = 1 pcs.
Q1: BC549-NPN 40V 0.5A transistors = 1 pcs.
Q2, Q3: IRF540-N CHANNEL POWER MOSFET, 100V, 27A, TO-220; 2 pcs.
C1,C2: 0.1uF 100V mylar capacitors = 2 pcs.
0.5W resistor
R1: 4.7K = 1 pcs.
R2: 120K = 1 pcs.
R3,R4: 1K = 2 pcs.
R5: 5.6K = 1 pcs.
T1: 2A 12V CT 12V transformer = 1 pcs.

Building and testing of 555 inverter circuit using MOSFET

In this project, I assemble components on a universal PCB board. As Figure 2, while operating it will get a little hot. So be sure to use enough heatsink.

555 inverter on universal PCB board

Figure 2

Then, check the circuit for errors. Please watch the video below.

When checking all no error

We will test it with a 100 watts lamp at the output, with a 12V battery as a source. You will see that the lamp glows. But the battery voltage is slightly low, so the AC voltage output is 190V.

After that, We check waveform is a square wave as shown on the scope.

Some people wonder about something. I will share it with you.

I put the 470uF 50V electrolytic capacitors to filter the current.
It does not need if you use a 12V 10Ah battery. Because it is a stable power current source.

Ideally, if you need full 100 watts output. You need to use 8A transformer. Because of input watts = output watts = 100 watts.

When the primary coil voltage of the transformer is 12V at 100 watts.
The output current input = 100W/12V = 8A (approximately)

555 Inverter circuit project

If it not working
I feel bad if you have built this project and it does not work.

First, you need to review the pin of the IC, resistors, and
capacitors. And importantly is how you connect the MOSFET.

View using IRF540 legs.

Second, should do not connect the power cord to the transformer and MOSFET.

Third, check the 555 timers working, and frequency generators at pin 3 first. You may use a voltmeter to measure a voltage across pin 3 and the ground. You use surely oscilloscope to watch waveform.

Check out these related articles, too:


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176 thoughts on “Make Simple 555 Inverter circuit using MOSFET”

  1. thanks for sharing the circuit
    is there a simple way to make some changes to make the frequency adjustable?
    with a potentiometer or something?

  2. Sir,when i calculated the frequency using F= 1 / 0.693 * C * ( Ra + 2Rb ) ,where Ra = 4.7K , Rb = 120k and C = 0.1u , i got 58.97Hz instead of 50Hz. Please help me. Thanks

  3. Hello sir.. Im trying to make this inverter using all the component listed in the above section, but i fail to produce th 220v ac.. I just want to ask.. Is there any unlisted component because when i look closer to ur circuit, there is a big black capacitor-like component. I hope u can explain about it.. Tq!

  4. hi according to the power relation p=i*v ,where i is current & v is voltage
    but here if we use 12-ct-12v 2amps transformer we get only 24w of output how can we get 100watts of output power (p=2amp*12volts
    =24watts) ???

  5. > Hi good friends,i have a ups with 24v battery and wont to convert it to
    > inventer to power my 110v fridge thank you.

    Hi, James Abeaku okine
    I not have a 12V to 110V inverter circuit example show you.
    If you have free time you may be test your ups circuit.
    and modify them.

    or you may remove the transformer.
    To adapt circuit into this circuit

    But you must to use zener diode or IC7812 to reduce voltage of 24V battery to 12V to supply the IC555 only.

    I am sorry for circuit ideas (in image form) since now I take my family to weekend Holiday.



  6. hello Admin,

    I have made d circuit and every thing is ok…but when i put the +ve terminal its sparks and flash the 220V 20W bulb while one of the mosfets becomes very very hot and starts smoking.

    Pls help ….thanks

  7. Hi Momename
    If I connect the 8.3A transformer, then should I increase the no. of mosfet, or may I use the 8.3A 12V 100w transformer with the same circuit. Pls let me know ASAP..

  8. Hi,Anjan Chatterjee
    Thanks for visit.
    Ideally, the mosfet can drive 27A maximum.
    But we may connect them in parallel x4 pcs.
    Normal current each mosfet is 2A so easy to drive load.

    If this project work please send your photo to me.

  9. Thanks for your kind feedback Momename. I actually want to use this circuit as a travelling battery charger(phone, dslr)where I connect solar panel (12V, 70-80watt) as source. I will connect the battery charger as load, I think the charger don’t get to much watt. So I think I easily use this circuit. **Pls correct me If I am wrong..
    *should I send My photo or the mentioned project photo ?

  10. Hi momename
    Thanks for your feedback..I previously checked that project. But I don’t want to carry the battery. I thought I simply connect the 12v 7-8ah solar panel directly with your this circuit(source). If I do so then will the circuit work ? I dont need power at night.
    Thanks A lot for helping me…

  11. Hi In your circuit diagram you mention Two +12 volt Dc Terminal/Point. But In your Figure 2 You put Providing +12 Volt Dc Only one Point. Can You Pls Tell Me Is The Diagram Right ? Should I provide +12 in both terminal or should I Provide +12V in one & another with -12V. And Pls also mention the points where I have to provide The +/-12 Volt in the circuit.
    waiting for your reply..

  12. If i use 8 amp of transformer then i have to use 2 pair of mosfet?
    how many power i will get after doing this…
    Pls ans me as soon as possible,,,,…….

  13. Hi,prits
    Thanks for your feedback.
    If you ue transistor, you should too many transistors.
    In this case you may use darington transistors.

  14. Dear Sir,
    I have build this circuit and it works absolutely fine. Kindly suggest me a battery charger circuit which i could use with this circuit and if possible suggest me how to convert this square wave inverter to a sine wave inverter.

    Santanu Dey

  15. Very simple Example of inverter working principle, thank you so much sir. small doubt sir instead of single transformer can we use 2 transformers in series? please rectify my doubt

  16. Dear Sir,
    Thanks for your reply. Could you suggest me a battery (12v/7.2AH) charger circuit which I could use along with this inverter circuit.

    Santanu Dey

  17. hi all,if i use a 50Amps transformer will the circuit still work fine,P=IV so 500W=I x 12v which gives 50Amps & also what if i use pair of transformers in series.

  18. Dear Sir,
    Could you tell me if I want use that 470uf electrolytic capacitor, where should I place that in diagram?
    Could you send me the new diagram with that capacitor or your PCB and schematic files?

  19. i have make this circuit. but this circuit is not working probably. the main problem is that ic only gives the positive voltage and does not give ground so can you plz solve the problem. what is the problem with pin 3 or ic? plz reply i am waiting for your reply.

  20. Hi, did you check how much efficient is this circuit how much watts draws at primary winding and how much provides at secondary winding

  21. Sir,thanks for the circuit. I want to know the advantage of a sine wave over a square wave inverter. Please help me. Elijah

  22. iam very happy with this, but sir the two types of the inverters i make them no any problem but sir they can’t take RED Globe.plc sir can we start communicating in other to help me with some or many ideas thanks so much (+2347064396921)

  23. Dies ist eine wirklich interessante Schaltung. Sie sollten diese zum PATENT anmelden. Der Wirkungsgrad von mehr als 400 Prozent ist wirklich bemerkenswert. ‘The transformer I use 2A current and 12V input at output power more than 100 watts.’
    Erreichen Sie diesen hohen Wirkungsgrad durch die unsymmetrische Ansteuerung des Transformators?
    Ich habe da einen Vorschlag für Sie. Erzeugen Sie aus den 220V wieder die 12V Speisespannung. Sie haben dann noch genug Energie über, die Sie weiter verwenden können. Gehen Sie aber sicher, daß Sie alle überschüssige Energie entnehmen. Ansonsten könnte ihnen die Schaltung aufgrund des Energieüberschusses explodieren.
    Viel Spaß, Baltuodis.

  24. Plz sir i want to construct a 1000watt 12VDC-220VAC inverter, (normal and fast) charging plus mosfet and circuit all on P.C.B Module i nid ur help

  25. how sure is this circuit because i have build some many circuit from the internet not 1 pl’s will this circuit work?

  26. hi
    at first thanks for this simple i have a problem.from this circuit i get square wave output voltage is very small,in mv.please give me a proper is very urgent.

  27. i want to know output and working of each component.hw dc is converting into ac,hw mosfet works.wt output thy give..coplete function of each components along wid output

  28. Hi I want to build a inverter few year ago but i can’t find a easy to build circuit.But now i find this assome circuit.Now i can build this.
    Thanks for the project.

  29. pls sir, your circuit worked well but I discovered that when I added more load, d voltage decreased. how can we make up for this pls? I believe if we can initiate a feedback unit, it will solve this problem. so where and how do we apply the feedback pls? work on this because its necessary sir.

  30. this circuit is very good. i tried it …it works good but very less efficiency..
    q2 is very hot but q3 is very cool…may i know the reason please…i have used 3 amp 12-0-12 transformer.

  31. Hi sir, i saw ur project as simple and I feel in love with it,so I decided to practicalise it.I used IRF2807 instead of IRF540N and BC547 instead of BC549 bt the bulb jst light on for a few seconds n went off.since then I’ve been troubleshooting it bt cnt find where the problem lies.pls cn u help me with a solution ASAP.I really need it

  32. IC 555 Timer Calculator with formulas & Equations IC 555 Timer Calculator with formulas & Equations IC 555 Timer Calculator with formulas & Equations

    Formulas and Equations for This calculator

    Frequency (f) = 1/ [ ln(2) x C x (R1 + 2R2) ]

    Frequency (f) = 1.44 / C x (R1 + 2R2) …. Where… 1/ ln(2) = 1.44

    This formula putting and get 58.9hz frequency in output 3no. pin on 555 ic why this inverter out frequency 50 hz

  33. I made this circuit …but the output from the MOSFETs have only one output at a time ..Both MOSFETs don’t get ON simultaneously …What to do ..I have used BC 547 in place of BC 549

  34. My circuit is working but the only problem is that when i reomove and again give ground then bulb blinks but it doesnt remained ON … what can i do? please help asap!

  35. I use bc547 but I notice it’s only one get switch but d other fet is off d volt frm 5.6k didn’t feed the 547 pls what should u do thanks

  36. finally!! After so long it worked. hey guys, one extra capacitor(470uf, 50v) is used in the circuit is important. it is used as a filter and you can connect its negative and positive through the dc supply’s -ve and +ve respectively.

    NOTE: It do not required, if you use 12V battery 10Ah because it is stable power current source.

  37. i made the circuit properly as mentioned ,every components are of equal as given value but it is not generating 220v and transformer is heating very much .what to do please help me??

  38. i made this circuit everything is placed correctly of right value but the circuit is not generating 220v ac and the transfermer also get heated very much.please help!!

  39. If i want use 40 volts dc voltage as input voltage then what is the rating of all components like resister, capacitor etc….
    Plz rpy me immediately…..

  40. Hi bro, I like the concept you use to design circuit. I fabricate the same circuit with the same spec of all the component as you used but instead of using 12-0-12 2A transformer, I choose to use 12-0-12 4A transformer. In software simulation, I have tried using Multisim and Proteus. Sorry to say the simulation was failed. The result in real time hardware fabrication is a positive. I manage to light up a bulb but the waveform generate from oscilloscope is clamping not a square wave. The light which lights up keeps flicker. I used 12v 7.2AH battery. Did you manage to simulate this circuit in software? If so, please reply me. Thank you.

  41. Please help.
    Tell me the diagram that has 470 capacitor connections. My voltage is 100 volts. The first one is the project. I am weiting your ancestor … Please help.

  42. I connected the circuit as illustrated but whenever i connect it to the battery which is 12V 7Ah, the wires heat up and burn and no output from transformer. Please help

  43. Dude, either your cap is way out of tolerance or your math is off. A 4.7K resistor for R1 results in 58.97 Hz by calculation. If peeps are putting 60 Hz into a 50 Hz transformer, they’ll have problems.

      • YW. By calculation (results will vary depending on component tolerances) a good combo of common parts would be 0.2 uf (2 x 0.1 in parallel), 100 Ohm for R1 and 72K (39K and 33K in series) for R2. That calculates to 50.069 Hz with a 50.03 duty cycle. That’s smart bomb accuracy if your tolerances work out. Otherwise that should get folks close enough.

    • Hi,
      Yes, you can I just read datasheet of SW50N06: on TO-220
      FeaturesN-Channel MOSFETBVDSS (Minimum)RDS(ON) (Maximum)IDQg (Typical)PD (@TC=25 ): 60 V: 0.023ohm: 50 A: 30 nc: 130 W

      You may try it. Please cheack leg it again. I sure you can do it.

  44. Hii, i have one doubt that this circuit output is 50hz sinusoidal or sqare wave? Please help me solve this problem, as i also wanted to charge my mobile phone using this and mobile charger required only sinusoidal input.
    Thanks and regards


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