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12V DC to 220V AC Converter [Tested Circuit]

Inverters are often needed at places where it is not possible to get AC supply from the Mains. An inverter circuit is used to convert the DC power to AC power. Inverters can be of two types True/pure sine wave inverters and quasi or modified inverters. These true /pure sine wave inverters are costly ,while modified or quasi inverters are inexpensive.

These modified inverters produce a square wave and these are not used to power delicate electronic equipments . Here, a simple voltage driven inverter circuit using power transistors as switching devices is build, which converts 12V DC signal to single phase 220V AC.

12V DC to 220V AC Converter Circuit Principle

The basic idea behind every inverter circuit is to produce oscillations using the given DC and apply these oscillations across the primary of the transformer by amplifying the current. This primary voltage is then stepped up to a higher voltage depending upon the number of turns in primary and secondary coils.

Also get an idea about 12V to 24V DC Converter Circuit

Inverter circuit Using Transistors

Inverter output

A 12V DC to 220 V AC converter can also be designed using simple transistors. It can be used to power lamps up to 35W but can be made to drive more powerful loads by adding more MOSFETS.

The inverter implemented in this circuit is a square wave inverter and works with devices that do not require pure sine wave AC.

Circuit Diagram

12v to 220v inverter cirucit


Inverter Circuit

Components required

  • 12v Battery
  • MOSFET IRF 630 -2
  • 2N2222 Transistors
  • 2.2uf capacitors-2
  • Resistor
    • 680 ohm-2
    • 12k-2
  • 12v-220v center tapped step up transformer.


The circuit can be divided into three parts: oscillator, amplifier and transformer. A 50Hz oscillator is required as the frequency of AC supply is 50Hz.

This can be achieved by constructing an Astable multivibrator which produces a square wave at 50Hz. In the circuit, R1, R2, R3, R4, C1, C2, T2 and T3 form the oscillator.

Each transistor produces inverting square waves. The values of R1, R2 and C1 (R4, R3 and C2 are identical) will decide the frequency. The formula for the frequency of square wave generated by the astable multivibrator is

F = 1/(1.38*R2*C1)

The inverting signals from the oscillator are amplified by the Power MOSFETS T1 and T4. These amplified signals are given to the step-up transformer with its center tap connected to 12V DC.

Output Video

The turns ratio of the transformer must be 1:19 in order to convert 12V to 220V. The transformer combines both the inverting signals to generate a 220V alternating square wave output.

By using a 24V battery, loads up to 85W can be powered, but the design is inefficient. In order to increase the capacity of the inverter, the number of MOSFETS must be increased.

To design a 100 watt Inverter read  Simple 100 Watt inverter

12v DC to 220v AC Converter Circuit Using Astable Multivibrator

Inverter circuits can either use thyristors as switching devices or transistors.  Normally for low and medium power applications, power transistors are used. The reason for using power transistor is they have very low output impedance, allowing maximum current to flow at the output.

One of the important applications of a transistor is in switching.  For this application, the transistor is biased in saturation and cut-off region.

When the transistor is biased in saturation region, both the collector emitter and collector base junctions are forward biased. Here the collector emitter voltage is minimum and collector current is maximum.

Another important aspect of this circuit is the oscillator. An important use of 555 Timer IC is in its use as an astable multivibrator.

An astable multivibrator produces an output signal which switches between the two states and hence can be used as an oscillator. The frequency of oscillation is determined by the values of capacitor and resistors.

[Also Read: How To Make an Adjustable Timer ]

 Circuit Diagram

Circuit Diagram of 12v DC to 220v AC Converter
Circuit Diagram of 12v DC to 220v AC Converter – ElectronicsHub.Org

Circuit Components

  • V1 = 12V
  • R1 = 10K
  • R2 = 150K
  • R3 = 10Ohms
  • R4 = 10Ohms
  • Q1 = TIP41
  • Q2 = TIP42
  • D1 = D2 = 1N4007
  • C3 = 2200uF
  • T1 = 12V/220V step up transformer

Circuit Design Explanation

Oscillator Design:An astable multivibrator can be used as an oscillator. Here an astable multivibrator using 555 timer is designed. We know, frequency of oscillations for a 555 timer in astable mode is given by:

f = 1.44/(R1+2*R2)*C

where R1 is the resistance between discharge pin and Vcc, R2 is the resistance between discharge pin and threshold pin and C is capacitance between threshold pin and ground.  Also the duty cycle of the output signal is given by:

D = (R1+R2)/(R1+2*R2)

Since our requirement is f =50Hz and D = 50% and assuming C to be 0.1uF, we can calculate the values of R1 and R2 to be 10K and 140K Ohms respectively. Here we prefer using a 150K potentiometer to fine tune the output signal.

Also a ceramic capacitor of 0.01uF is used between the control pin and ground.

Switching Circuit Design:Our main aim is to develop an AC signal of 220V. This requires use of high power transistors to allow the flow of maximum amount of current to the load. For this reason we use a power transistor TIP41 with a maximum collector current of 6A, where the base current is given by the collector current divided by the DC current gain.  This gives a bias current of about 0.4A *10, i.e.4A. However since this current is more than the maximum base current of the transistor, we prefer a value less than the maximum base current. Let us assume the bias current to be 1A. The bias resistor is then given by

Rb = (Vcc – VBE(ON))/Ibias

For each transistor, the VBE(ON) is about 2V. Thus Rb for each is calculated to be 10 Ohms. Since the diodes are used for biasing, the forward voltage drop across the diodes should be equal to the forward voltage drops across the transistors. For this reason, diodes 1N4007 are used.

The design considerations for both the PNP and NPN transistors are same. We are using a PNP power transistor TIP42.

Output Load Design: Since the output from the switching circuit is a pulse width modulated output, it might contain harmonic frequencies other than the fundamental AC frequency. For this reason, an electrolyte capacitor needs to be used to allow only the fundamental frequency to pass through it. Here we use an electrolyte capacitor of 2200uF, large enough to filter out the harmonics. Since it is required to get 220V output, it is preferred to use a step up transformer. Here a 12V/220V step up transformer is used.

12v DC to 220v AC Converter Circuit Operation

  • When this device is powered using the 12V battery, the 555 timer connected in astable mode produces square wave signal of 50Hz frequency.
  • When the output is at logic high level, diode D2 will conduct and the current will pass through diode D1, R3 to the base of transistor Q1.
  • Thus transistor Q1 will be switched on. When the output is at logic low level, diode D1 will conduct and current will flow via and D1 and R4 to the base of Q2, causing it to be switched on.
  • This allows the DC voltage to be produced across the primary of the transformer at alternate intervals. The capacitor ensures that the frequency of the signal is at the required fundamental frequency.
  • This 12V AC signal across the primary of the transformer is then stepped up to 220V AC signal across the transformer secondary.

Applications of 12v DC to 220v AC Converter Circuit

  1. This circuit can be used in cars and other vehicles to charge small batteries.
  2. This circuit can be used to drive low power AC motors
  3. It can be used in solar power system.


  1. Since 555 Timer is used, the output may slightly vary around the required duty cycle of 50%, i.e. exact 50% duty cycle signal is hard to achieve.
  2. Use of transistors reduces the efficiency of the circuit.
  3. Use of switching transistors has the possibility of causing cross over distortion in the output signal. However this limitation has been reduced to some extent by the use of biasing diodes.


Instead of 555 timer one can use any astable multivibrator. For example this circuits can also be build using 4047 astable multivibrator,whose output current is amplified and applied to the transformer.

[Read: Solar Inverter for Home]

106 Responses

      1. Hey I am build the ckt using IRF630 but the output of transformer gives 50v…I can’t understand vwhats the problem can any one tell me plz???

        1. the problem is that you are using low current holding component it holds up to 200 v but what about A what’s your value for A? may be that will help me solve your problem

  1. i need a electrical minor project but i am not understanding what should i present amd also i have no idea about it so please help me

  2. I design wxactly that circuit with input 16 volts..but across 2200 uF capacitor,the voltage A.C is 30 volts but transformer does not step up this voltage and i didnt found any voltage across transformer.

          1. i hv tried but on connecting transformer the 12v battery supply is being getted shorted ……..can u suggest what is the problem…………..i hv implemented the ckt as per the given dig. and transformer is also of the same rating

  3. i have constructed the circuit using multisim with transistors , TIP 41CG , And TIP 42CG but when i run the simulation switch the IC 555 timer output gets burst in the simulation . and i cannot see any output voltage across the transformer of course, How every i have thoroughly circuit once again but couldn’t find out where the problem is ?

    Can any one help me please where might the problem could be ?

    1. The inverter is designed for a power of 25-30W and the maximum current drawn will be less than 2A. The IRF630 can be used up to 9A (temperature dependent) of drain current. IRF540 can be used up to 28A of continuous drain current and IRF510 can be used up to 5.6A. So, IRF510 can be used in this circuit. If you are designing an inverter for higher power, then you can use IRF540.

    1. During the positive pulse, Q1 will be ON and the current flows from Q1 to T1 via C3. During this time, C3 will be charged and is in normal polarity. During the negative pulse, Q2 will be ON. C3 will discharge via Q2 and the flow of current will be from T1 to Q2 via C3. So, C3 will help in generating an alternating wave.

    1. Minimum current for the inverter circuit can be calculated by adding the current flowing in the circuit alone (without transformer) and the open circuit current of the transformer.

    1. The inverter is designed for a power of 25-30W and the maximum current drawn will be less than 2A. The IRF630 can be used up to 9A (temperature dependent) of drain current. IRF640 can be used up to 18A of continuous drain current. If you are designing an inverter for higher power, then you can use IRF640.

  4. I built and tested the dc to ac inverter using the 555 timer. I am getting a max of 6.36 Vac on the primary side of the transformer and 46 vac on the secondary side of the transformer. Do you have any idea what the issue may be? I have tinkered with the potentiometer with no luck. I have followed the instructions above. The only difference is that I am using a 12V to 120 V transformer. Thanks for your time.

    1. Disregard this comment as well, I understand what I was doing wrong after reading your post. I learned so much about transformers and astable multivibrators from doing this project. Keep up the good work.

  5. I built the same circuit (IRF 630), everything is ok except that output is just 55-60V instead of 220V.On primary side of transformer voltage is 24V,(which is the required voltage ) showing that the circuit is working fine.If I plug in transformer directly into 220 V mains it gives 24V which shows that transformer is also working fine.Please tell what is the problem.

  6. I built both DC to AC inverters and I understand most of it conceptually with the exception of the transistor, resistors, and capacitor acting as the oscillator. How do the transistor, resistor, and capacitor components make up the oscillator? Can you please explain? Thank you.

  7. how to many amps transformer can be used in first given circuit and also in other circuit using ic 555 timer

  8. Please give power rating of battery as well as transformer of the tested design.I want make this circuit but without power rating it is not possible

  9. does this inverter work becaue i made it but it did not work It gives 0 V output(irf630) if someones work please share

  10. pls sir if there is an increase in the number of MOSFET will there be an increase in the other components ie the equipment in other to be able to carry more load thanks

  11. What the type of the transformmer, i tried find at shop but they they said there were no transformer like that.. Can u describe the transformer the type??how much amp??

  12. Can you please tell me the ratings of transformer?…. What is the rated current of the transformer ?…

  13. This circuit is working but output power is very low. How can we improve the output power?(for inverter circuit using IRF630)

  14. We try this circuit ( irf630 ) we get 210 output but your shown breadboard connection are wrong so do your own connection as per circuit diagram ..n thank u .

  15. I am getting 110v output instead of 220v by using IRF630 nmosfet inverter circuit. How can i get 220v output ?

  16. If the input of my transformer is 12vdc and output 220vac current is 1.5A,
    1 what is the output wattage
    2 can I use the first circuit instead of the second
    3 what is the difference between the two circuits on this page since both are square wave.

  17. Hello i love your design, i designed it too with IRF 830 andi had a problem of incosistency.I mean the AC supply was not consistent once i plug the battery, and at a time one of my 2N2222 transistors burnt, pls any suggestions to solve my problem?

  18. These circuits are good for learning some basics of switching supplies but are not meant for anything else, or shouldn’t be meant for anything else. You will not get reliable operation from these types of circuits.

  19. which software avaliable for to designe and simulate the Circuit Diagram of 12v DC to 220v AC Converter

  20. Please I have a growatt inverter 5kva 48v HVM. It output frequency is 65hz as against the set 50hz. And when there is an input supply from the grid, the input voltage keeps dropping till the inverter starts showing error 10 which means output power derating. What component in the inverter can be the cause of this problem

  21. How to subscribe this page ? I like this page ❤️ and thanx for give same knowledge to me 😃

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