Make Simple 555 Inverter circuit using MOSFET

Do you want to learn a simple inverter circuit? The output is about 50 watts. And using a few parts and a small circuit.

Here is an IC 555 inverter circuit. Because of using 555 timer and MOSFET as main.  I experiment it to work well.

When use source is 12V battery will have the output of 220V AC 50Hz.

The principle of the circuit

I think many peoples do not like to read many words or long reading.
So please read at simple principle inverter

inverter working principle

Firstly, DC voltage from a battery gets into square wave oscillator circuit. It produces AC voltage, 50Hz frequency.  But this is too low current.

Recommended: 555 Astable pulse oscillator

What can you do? Use the power switchings such as the power transistors or MOSFETs.

But AC voltage still is 12V.   Next, Transformer inductance voltage to rises into 220V AC 50Hz to apply load.

How 555 inverter circuit works

In the circuit above is completely circuit diagram of this project. I use IC-NE555 timer is a square wave frequency generator output of 50Hz.

555 inverter circuit diagram with MOSFET

The frequency is determined with R2-resistor and C1-capacitor.

Output 555 Frequency Calculation

If you use R2 is 150K. It is 47HZ output. You may use a potentiometer-50K in series with R2. To adjust a frequency is 50HZ

MF4Me said:
“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
  • 72K (39K and 33K in series) for R2.
Calculation of 50HZ frequency of 555

That calculates to 50.069 Hz with a 50.03 duty cycle.

That is smart accuracy. If your tolerances work out.

What is more?

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

The output current at Pin 3 of IC1 will flow 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 inductance low AC voltage to high volts, about 220V to 250V.  According to the condition of the battery, 12V to 14.4V.

The circuit diagram of MOSFET Inverter

The transformer I use 2A current and 12V input at output power more than 100 watts.

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

Why use MOSFET?

In circuit 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 is the same as normal transistors, such as TIP41, 2SC1061 etc.
  2. It can drive high current to load, 27A max.  While the transistor (TIP41) can drive load 4A max.
  3.  It is inexpensive just 0.5US only.
  4. The body is TO-220 looks like TIP41 transistor so easy to mount on a heatsink.
  5. They can use smaller heatsink than a transistor, they are not too heat.

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

This projects I assemble components on a universal PCB board. As Figure 2, while it operated will get little hot. So use enough heatsink.

555 inverter on universal PCB board

Figure 2

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

When checking all no error

We will test it with 100 watts lamp at the output. Then, apply 12V battery source. You will see that. The lamp glows. But the battery voltage is slightly low. Also, 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 with you.

The electrolytic capacitors are 470uF 50V. I put it to filter a smooth current. It does not need. If you use a 12V battery, 10Ah. 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 uneasy if you build this project It does not work.

First, you need to review well, the pin of the IC, resistors, capacitors. And the important is connecting 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, frequency generators at pin 3 first. You may use a voltmeter to measure a voltage across pin 3 and ground. You use surely oscilloscope to watch waveform.

Check out these related articles, too:

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RK Chall

Nice. I will try it soon. ThanQ for publication


Very interesting, but I build K-bridge not center-tap.
nice work any way

Francisco Mateu

estimado amigo gracias por los envios de sus proyectos son muy util

Hi,RK Chall

Thanks for your feedback.

Hi,Francisco Mateu

Thanks for your feedback.


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

serunkuma shem

grate work

chayapol garaipoom

Hi serunkuma shem.
Thanks for your feed back.

ali khani

hi.sir thanks for inverter circuit.plz tell me another transistors if I don’t find irf540???


I love your work,it is great though i have nov tried it. But is the wave a square or sine. Thanks. Elijah


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

Fikrul Hakim

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!

sk sahabaj

i am searching for a simple easy inverter circuit & i get this i am so intersted i will made it to day…

sk sahabaj

the transformer whish is using is a normal transformer 220v to 12v or not…

sanjed arfin

i tried to make it but my 555 burded out and brust ed why ??

Hi, Sk sahabaj

Thanks for feedback.
Yes, your correct transformer.

Hi,sanjed arfin

I am sorry for your IC burded.

You should check pin of IC-555 it may short or incorrect places.

Thanks for you feed back.

sanjed arfin

c2 should be .01uf otherwise it will burn.

Hi,Sanjed arfin.

Thanks for feedback.

C2 is 0.01uF to 0.1uF it not burned.

I test really them.


Thanks for your feedback.

This circuit works surely.

as video is shown.


Thanks for your feedback.

Yes, you can use potentiometer for adjust output frequency.

Hi,RK Chall.
Thanks for your feedback.


Thanks for your feedback.

What about K-bridge?

Please tell me.

Hi,Francisco Mateu… My friend

Thanks for your feedback.

Hi,serunkuma shem

Thanks for your feedback.


Thanks for your feedback.

The output is square wave at around 50HZ-60HZ
You may use potentiomer for adjust frequency.

sk sahabaj

i can’t find irf540 please tell me the alternative of irf540..

@sk sahabaj.
IRF540 is N channel MOSFET that you can you any Mosfet which high current and voltage 33A 100V. I like it because very cheaper and easy to buy.


hi what can i do to increase the out put power to 200w

Thanks for your feedback.
You can add Mosfet in parallel to increase current driver transformer which must change is 2 times current.


hi admin thank u very much for your replay ,can u tell me how to add mosfets in parallel

Hi, V
You can add mosfets in parallel for increase current drive secondary coil of transformer.


do you think adding mosfets will increase the output power effectively

For me if add mosfet in parallel it will increase current to higher.
I should this mosfet because cheaper and easy to buy.


hi momename
can i use ne556 instead of ne555,because it is more efficient than ne555


hi sorry it is not ne556 it is ne7555 which is cosmos ic

Yes you can use NE7555 same NE555.


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) ???

I do not very good any principles,But I love Electronic, If I test it works, I will tell you.

> 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… Read more »


hi momename does the increase in gate current increases the output power


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


In the picture on the website, you used an electrolytic capacitor…?

You may increase current drive transformer with add mosfet next one in parallel.

Thanks for your feedback.
Please check connection of mosfet, they may wrong lead.

Sekhar ndk

hai momename
can we use it for fan in home?


what will be the output if i connect 12v/ 70AH
and i need ahelp for making an 1500W inverter


please tall me meaning of ct


Work but 60 watt bulb is very dim not full

Thanks for your feedback.
If you need full watt ouput.
You must use 100W = 12V x I? transformer.
or 8.3A input transformer.


Using 3 capasitor and what diagram of third capasitor

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