The article explains a very simple yet powerful 150 watt inverter circuit design which can be built by any electronic enthusiast and used for powering most of the household electrical appliances (resistive).
Contents
Introduction
Calculating MOSFET parameters may seem to involve a few difficult steps, however by following the standard design enforcing these wonderful devices into action is definitely easy.
When we talk about inverter circuits involving power outputs, MOSFETs imperatively become a part of the design and also the main component of the configuration, especially at the driving output ends of the circuit.
Inverter circuits being the favorites with these devices, we would be discussing one such design incorporating MOSFETs for powering the output stage of the circuit.
Referring to the diagram, we see a very basic inverter design involving a square wave oscillator stage, a buffer stage and the power output stage.
The use of a single IC for generating the required square waves and for buffering the pulses particularly makes the design easy to make, especially for the new electronic enthusiast.
Using IC 4093 NAND Gates for the Oscillator Circuit
The IC 4093 is a quad NAND gate Schmidt Trigger IC, a single NAND is wired up as an astable multivibrator for generating the base square pulses. The value of the resistor or the capacitor may be adjusted for acquiring either a 50 Hz or 60 Hz pulses. For 220 V applications 50 Hz option needs to be selected and a 60 Hz for the 120 V versions.
The output from the above oscillator stage is tied with a couple of more NAND gates used as buffers, whose outputs are ultimately terminated with the gate of the respective MOSFETs.
The two NAND gates are connected in series such that the two mosfets receive opposite logic levels alternately from the oscillator stage and switch the MOSFETs alternately for making the desired inductions in the input winding of the transformer.
Mosfet Switching
The above switching of the MOSFETs stuffs the entire battery current inside the relevant windings of the transformer, inducing an instant stepping up of the power at the opposite winding of the transformer where the output to the load is ultimately derived.
The MOSFETs are capable of handling more than 25 Amps of current and the range is pretty huge and therefore becomes suitable driving transformers of different power specs.
It’s just a matter of modifying the transformer and the battery for making inverters of different ranges with different power outputs.
Parts List for the above explained 150 watt inverter circuit diagram:
R1 = 220K pot, needs to be set for acquiring the desired frequency output.
R2, R3, R4, R5 = 1K,
T1, T2 = IRF540
N1—N4 = IC 4093
C1 = 0.01uF,
C3 = 0.1uF
TR1 = 0-12V input winding, current = 15 Amp, output voltage as per the required specs
Anonymous says
thanks sir but the lamps work from 1500 to 2500vca and this circuit is 220Vac
Anonymous says
hi, what is the value of diodes?
Anonymous says
Sir, if I would not like to connect the diodes so both the mosfet's Source will be short circuit to each other while each end of the transformer input will be connected to the Drain directly respectively?
Anonymous says
hi,
This is only 1 IC? no more LM555?
Anonymous says
Hi Sir Swagatam,
can i use IRFZ44n for mosfets?
Ragards
Swagatam says
Yes you can use it.
Anonymous says
hi sir…could you pls explain me how these mosfets work…i couldnt understand…
Swagatam says
The Nchannel mosfets in the above circuit switch ON in response to positive triggers which are applied alternately from the respective NAND gates.
The two mosfets thus trigger alternately and load the respective winding of the transformer with the battery voltage/current, generating the required actions across the output winding of the transformer.
shankar says
sir what is the function of ic circuit.
Swagatam says
for generating square wave oscillations…
jebas says
sir did u finished 1000w circuit
Swagatam says
No I did not start yet..is it a square wave or a sine wave that you need.
L SRIKRISHNA says
sir,
can you please provide the step by step procedure with diagram
Swagatam says
I have explained the circuit in the article, if you have specific questions you may ask it here…
Pranav BM says
Swagat Ji, can you mention the legs of the IC with the gates or give a schema with typical IC pinout form
Swagatam says
Pranav, please refer to the datasheet of IC 4093, you will find the pin outs of the relevant gates, you may position the particular gates as per your preference as all four of them are identical…
Pranav BM says
thank you, shall check with http://www.alldatasheet.com, any other link available?
Anonymous says
Dear Swagatam Majumdar Saab
Namashkaar
Please provide me the details of the ordinary Step-Down Transformer ( as used for Audio Amplifier Circuit ) and that of Inverter Step-Up Transformer ; I mean – I wish to ask / clarify – that – whether the following is correct : Step-Down Transformer : Primary is for 220VAC and the winding is thin gauge copper wire – say 36 gauge – with more number of turns – say approx 1500 and Secondary is for say 12VAC with Center Tap – and the winding is thick gauge copper wire – say 18 gauge – with lesser number of turns – say approx 200 to 250 or so ; ; Step-Up Inverter Transformer : Primary is for 12VAC with Center Tap and the winding is thin gauge copper wire – say 24 gauge – with lesser number of turns – say approx 600 and Secondary is for – say 220VAC and the winding is thick gauge copper wire – say 12 gauge – with more number of turns – say approx 1800 to 2000 or so ; please correct me if i am wrong ; looking eagerly for your reply ; also mention the core / lamination Diameter / size and the total number of lamination plates that should be used ; GOD Bless You – in Advance – for your valuable information. My Blessings and wishes too ;-D
Swagatam says
Helio, Thanks!
An ordinary step down transformer can be used for inverter application by connecting the low voltage side to the inverter circuit.
Special designing may not be required as they are readily available in the market.
I you are looking for a customized design, you may consult a qualified transformer designer/maker because I do not have much experience with transformer designing.
viki says
hi
iam thinking of designing an inverter that runs one ceiling fan and one light……how can i do that and how much load the fan takes? do ceiling fan and table fan takes differnt load
Swagatam says
hi
you can make the above circuit, table fan and ceiling fan have different wattages, may depend on size and make.
Anonymous says
can i have my use this circuit to run my television?
Swagatam says
No….
Anonymous says
so what all apliances can i use here?
Swagatam says
lights and fan only
Anonymous says
sir will you please kindly give a rough sketch of the prices of the items used here !!
please sir i am asking it so that i wont get cheated when i go to the electronics shop ,….
Swagatam says
total will be around Rs.800/- without battery
Anonymous says
sir when dc supply will be directly provided to a transformer the primary winding will burn out destroying the transformer.
my question is that can we test the circuit before i connect the mosfets to my transformer?
Anonymous says
sir what will be cost of the transformer about?
Swagatam says
the battery is not directly connected to the transformer, it will get switched through the mosfets.
teewah says
hi,
i my mosfets get sparks and smoke on connection to transformer and battery. what could be wrong?
Swagatam says
either your circuit oscillator is not working or the mosfets are put the wrong way….pls check these issues.
Anonymous says
Do we feed an external input signal to pin 7 and pin 14.
Swagatam says
No, it's taken from the battery itself as shown in the diagram.
Anonymous says
am a electronics and communication engineering student……..now am going to work for an major project….can u suggest me circuit for my main project?
Swagatam says
If you can give me a hint, then probably i can suggest you a related circuit
Anonymous says
my project title is 'pc based electrical load controller' can u suggest me any circuit
Swagatam says
please provide detailed info about your requirement.
MisterKibz says
Dear sir,i have tried this circuit personally and trust me,one of the mosfets gets super hot while the other one still cool (dunno why?) but the sad thing is that my output I only got 193.4V instead of 230V and when i connected it another way I only get 96.5V instead of 150V….any chance why the output voltage quite low or any way of improving the efficiency of the circuit? Thanks in advance sir…..
Swagatam says
Dear Misterkibz,
there could be something wrong in your circuit, check the voltages at the gates of the mosfets, they should be nearly equal, if the difference is more than 2V, then certainly either the IC or your mosfet could be faulty. Once you rectify this issue, the output voltage will automatically get corrected.
Anonymous says
can u suggest me cut off circuit for stop charging to battery after it gets charged pls
Swagatam says
https://homemade-circuits.com/2012/02/how-to-build-automatic-6-volt-12-volt.html
Anonymous says
is this cut off circuit is suitable for this simplest 150 watts inverter
Swagatam says
it has no connection with an inverter, it's related to the battery used.
Anonymous says
dear sir. i also tried this circuit personally same would happend to me.the mosfet gets super hot and burns out but the another mosfet is stay cool. i checked the burned mosfet drain pin is fully blacked….and also i have one doubt how to check the gate, drain and source value
Swagatam says
use DMM DC voltage range, connect red prod to gate and black prod to batt negative
surya smart says
dear sir,
i want a circuit that was related to 'RFID based vehicle security and locking system
Swagatam says
Dear Surya,
RFID is as good as a RF remote system, so why not go for a Rf remote control, it's much simpler and efficient. You may refer to the following post:
https://homemade-circuits.com/2013/07/simple-100-meter-rf-module-remote.html
shehna falila says
can we add a battery charger to charge the battery along with the inverter circuit? so that when the inverter is not in use the battery can be charged up. if it's possible, can you please provide the circuit diagram ? thanks
Swagatam says
you can try the following circuit, it is designed to produce an automatic changeover for the same:
https://homemade-circuits.com/2014/06/how-to-convert-inverter-to-ups.html
fidel catsro says
hi swatagam, can this schematics be used as a 1000 watt inverter with the right transformer and super battery and adequate cooling of the transistor without changing the schematics?
Swagatam says
Hi Fidel, yes it can be done!
and the unused gate can be further modified to generate PWMs for transforming the design into a pure sine wave inverter.
Ganimid Alvarez says
I am doing your solar inverter here: https://homemade-circuits.com/2012/02/how-to-make-solar-inverter-circuit.html from a 20 watt solar panel giving 12 DC.
My question is, Can I use a 4A/6A/8A 24-0-24 or 12-0-12 transformer and still get a 220 V AC output?
Swagatam says
if the output of the trafo is rated at 220V and if the input supply is a little higher than the 12-0-12 or 24-0-24 spec then the output will be adequately above 220V
jayam vivek says
Dear Sir , please say me how to connect mosfet in the inverter, for other switching application and all I am connecting the load at. drain side and also I need to know how to calculate the how much current which is flowing through mosfet?
Swagatam says
Dear jayam, It may be done as shown in the explained diagram above….gate goes to the signal source via a low value resistor……..drain to the transformer taps, and the source to the ground or the negative of the battery.
this set up is for all N channel mosfets which is the standard recommended type for inverter application.
jayam vivek says
Thanks for ur answer sir, pls tell me how to calculate current which is going through mosfet ? if I want to make 200w inverter means how to calculate the VA value of the output transformer?
Swagatam says
simply connect an ammeter in series with the battery positive…that will provide you with an instant indication regarding the amount current being used (delivered) by the inverter (load)
Battery (+)———-( A )—————->inverter
Dennis Chukwuma says
Hi,how many mosfets should i Use in building 2000w square wave inverter..i intend using irf260
Swagatam says
how much DC voltage do you intend to use??