7 Simple Inverter Circuits you can Build at Home

These 7 inverter circuits may look simple with their designs, but are able to produce a reasonably high power output and an efficiency of around 75%. Learn how to build this cheap mini inverter and power small 220V or 120V appliances such drill machines, LED lamps, CFL lamps, hair dryer, mobile chargers, etc through a 12V 7 Ah battery.

Let's begin with the most simplest in the list which utilizes a couple of 2N3055 transistors and some resistors.


1) Simple Inverter Circuit using 2N3055 Transistors and few Resistors


The article deals with the construction details of a mini inverter. Read to know regrading the construction procedure of a basic inverter which can provide reasonably good power output and yet is very affordable and sleek.

There may be a huge number of inverter circuits available over the internet and electronic magazines. But these circuits are often very complicated and hi-end type of inverters.

Thus we are left with no choice but just to wonder how to build power inverters that can be not only easy to build but also low cost and highly efficient in its working.

Well your search for such a circuit ends here. The circuit of an inverter described here is perhaps the smallest as far its component count goes yet is powerful enough to fulfill most of your requirements.






Construction Procedure



  • This simple mini inverter circuit can be completed through the following easy steps:

  • Cut two sheets of aluminum of 6/4 inches each.

homemade 2N3055 heatsink with C channel aluminum

  • Bend one end of the sheet as shown in the diagram. Drill appropriate sized holes on to the bends so that it can be clamped firmly to the metal cabinet.

  • If you find it difficult to make this heatsink you can simply purchase from your local electronic shop  shown below:

TO3 transistor heaksink

  • Also drill holes for fitting of the power transistors. The holes are 3mm in diameter, TO-3 type of package size.

  • Fix the transistors tightly on to the heatsinks with the help of nuts and bolts.

  • Connect the resistors in a cross-coupled manner directly to the leads of the transistors as per the circuit diagram.

  • Now join the heatsink, transistor, resistor assembly to the secondary winding of the transformer.

  • Fix the whole circuit assembly along with the transformer inside a sturdy, well ventilated metal enclosure.

  • Fit the output and input sockets, fuse holder etc. externally to the cabinet and connect them appropriately to the circuit assembly.

Complete Wiring Layout






simple inverter circuit wiring layout 100 watt using 2N3055 BJTs


Parts List


You will require just the following few components for the construction:

R1, R2= 100 OHMS./ 10 WATTS WIRE WOUND

R3, R4= 15 OHMS/ 10 WATTS WIRE WOUND

T1, T2 = 2N3055 POWER TRANSISTORS (MOTOROLA).

TRANSFORMER= 9- 0- 9 VOLTS / 8 AMPS.

AUTOMOBILE BATTERY= 12 VOLTS/ 10AH

ALUMINUM HEATSINK= CUT AS PER THE REQUIRED SIZE.

VENTILATED METAL CABINET= AS PER THE SIZE OF THE WHOLE ASSEMBLY


How to Test it?



  • The testing of this mini inverter is done in the following method:

  • For testing purpose connect a 60 watt incandescent bulb to the output socket of the inverter.

  • Next, connect a fully charged 12 V automobile battery to its supply terminals.

  • The 60 watt bulb should immediately light up brightly, indicating that the inverter is functioning properly.

  • This concludes the construction and the testing of the inverter circuit.

  • I hope from the above discussions you must have clearly understood how to build an inverter which is not only simple to construct but also very affordable to each of you.

  • It can be used to power small electrical appliances like soldering iron, CFL lights, small portable fans etc. The output power will lie in the vicinity of 70 watts and is load dependent.

  • The efficiency of this inverter is around 75%. The unit may be connected to your vehicles battery itself when outdoors so that the trouble of carrying an extra battery is eliminated.

Simulation and Working


The functioning of this mini inverter circuit is rather unique and different from the normal inverters which involve discrete oscillator stage for powering the transistors.

However here the two sections or the two arms of the circuit operate in a regenerative manner. Its very simple and may be understood through the following points:

The two halves of the circuit no matter how much they are matched will always consist a slight imbalance in the parameters surrounding them, like the resistors, Hfe, transformer winding turns etc.

Due to this, both the halves are not able to conduct together at one instant.

Assume that the upper half transistors conduct first, obviously they will be getting their biasing voltage through the lower half winding of the transformer via R2.

However the moment they saturate and conduct fully, the entire battery voltage is pulled through their collectors to the ground.

This sucks-out dry any voltage through R2 to their base and they immediately stop conducting.

This gives an opportunity for the lower transistors to conduct and the cycle repeats.

The whole circuit thus starts to oscillate.

The base Emitter resistors are used to fix a particular threshold for their conduction to break, they help to fix a base biasing reference level.

The above circuit was inspired from the following design by Motorola:







Output Waveform better than square wave (Reasonably suitable for all electronic appliances))



PCB Design for the above explained simple 2N3055 Inverter Circuit (Track Side Layout)




simple inverter PCB layout

More Easy to Build Inverter Circuits


2) Using IC 4047




4047 simple inverter circuit

As shown above a simple yet useful little inverter can be built using just a single IC 4047. The IC 4047 is a versatile single IC oscillator, which will produce precise ON/OFF periods across its output pin#10 and pin#11. The frequency here could be determined by accurately calculating the resistor R1 and capacitor C1. These components determine the oscillation frequency at the output of the IC which in turn sets the output 220V AC frequency of this inverter circuit. It may set at 50Hz or 60Hz as per individual preference.

The battery, mosfet and the transformer can be modified or upgraded as per the required output power specification of the inverter.

For calculating the RC values, and the output frequency please refer to the datasheet of the IC

3) Using IC 4049




IC 4049 pinout details





simple inverter circuit using IC 4049

In this simple inverter circuit we use a single IC 4049 which includes 6 NOT gates or 6 inverters inside. In the diagram above N1----N6 signify the 6 gates which are configured as oscillator and buffer stages. The NOT gates N1 and N2 are basically used for the oscillator stage, the C and R can be selected and fixed for determining the 50Hz or 60 Hz frequency as per country specs

The remaining gates N3 to N6 are adjusted and configured as buffers and inverters so that the ultimate output results in producing alternating switching pulses for the power transistors. The configuration also ensures that no gates are left unused and idle, which may otherwise require their inputs to be terminated separately across a supply line.

The transformer and battery may be selected as per the power requirement or the load wattage specifications.

The output will be purely a square wave output.

Formula for calculating frequency is given as:

f = 1 /1.2RC,

where R will be in Ohms and F in Farads

4) Using IC 4093




pinout number and working details of IC 4093












Quite similar to the previous NOT gate inveter, the NAND gate based simple inverter shown above can be built using a single 4093 IC. The gates N1 to N4 signify the 4 gates inside the IC 4093.

N1, and N2 are wired as an oscillator circuit, for generating the required 50 or 60Hz pulses. These are appropriately inverted and buffered using the remaining gates N2, N3, N4 in order to finally deliver the alternately switching frequency across the bases of the power BJTs, which in turn switch the power transformer at the supplied rate for generating the required 220V or 120V AC at the output.

Although any NAND gate IC would work here, using the IC 4093 is recommended since it features  Schmidt trigger facility, which ensures a slight lag in switching and helps creating a kind of dead-time across the switching outputs, making sure that the power devices are never switched ON together even for a fraction of a second.

5) Another Simple NAND gate Inverter using MOSFETs


Another simple yet powerful inverter circuit design is explained in the following paragraphs which can be built by any electronic enthusiast and used for powering most of the household electrical appliances (resistive and SMPS loads).

The use of a couple of mosfets influences a powerful response from the circuit involving very few components, however the square wave configuration does limit the unit from quite a few useful applications.

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

Formula for calculating frequency will be identical to the one described above for IC 4049.

f = 1 /1.2RC. where R = R1 set value, and C = C1

6) Using IC 4060


4060 inverter circuit

If you have a single 4060 IC in your electronic junk box, along with a transformer and a few power transistors, you are probably all set to create your simple power inverter circuit using these components. The basic design of the proposed IC 4060 based inverter circuit can be visualized in the above diagram. The concept is basically the same, we use the IC 4060 as an oscillator, and set its output to create alternately switching ON OFF pulses through an inverter BC547 transistors stage.

Just like IC 4047, the IC 4060 requires an external RC components for setting up its output frequency, however, the output from the IC 4060 are terminated into 10 individual pinouts in a specific order wherein the output generate frequency at a rate twice that of its preceding pinout.

Although you may find 10 separate outputs with a rate of 2X  frequency rate across the IC output pinouts, we have selected the pin#7  since it delivers the fastest frequency rate among the rest and therefore may fulfil this using standard components for the RC network, which may be easily available to you no matter in which part of the globe you are situated in.

For calculating the RC values for R2 +P1 and C1 and the frequency you can use the formula as described below:





Here's yet another cool DIY inverter idea which is extremely reliable and uses ordinary parts for accomplishing a high power inverter  design, and can be upgraded to any desired power level.

Let's learn more about this simple design

7) Simplest 100 Watt Inverter for the Newcomers


The circuit of a simple 100 watt inverter discussed in this article can be considered as the most efficient, reliable, easy to build and powerful inverter design. It will convert any 12V to 220V effectively using minimum components

Introduction


The idea was published many years back in one of the elecktor electronics magazines, I present it here so that you all can make and use this circuit for your personal applications. Let's learn more.

The proposed simple 100 watt inverter circuit disign was published quite a long time ago in one of the elektor electronics magazines and according to me this circuit is one of the best inverter designs you can get.





I consider it to be the best because the design is well balanced, well calculated, utilizes ordinary parts and if done everything correctly would start working instantly.

The efficiency of this design is in the vicinity of 85% that's good considering the simple format and low costs involved.

Using an Transistor Astable as the 50Hz Oscillator


Basically the whole design is built around an astable multivibrator stage, consisting of two low power general purpose transistors BC547 along with the associated parts consisting of two electrolytic capacitors and some resistors.

This stage is responsible for generating the basic 50 Hz pulses required for initiating the inverter operations.

The above signals are at low current levels and therefore requires to be lifted to some higher orders. This is done by the driver transistors BD680, which are Darlington by nature.

These transistors receive the low power 50 Hz signals from the BC547 transistor stages and lift them at higher current levels so that it can be fed to the output transistors.

The output transistors are a pair of 2N3055 which receive an amplified current drive at their bases from the above driver stage.

2N3055 Transistors as the Power Stage


The 2N3055 transistors thus are also driven at high saturation and high current levels which gets pumped into the relevant transformer windings alternately, and converted into the required 220V AC volts at the secondary of the transformer.

2N3055 inverter 100 watt simple circuit


Parts List for the above explained simple 100 watt inverter circuit


R1,R2 = 27K, 1/4 watt 5%
R3,R4,R5,R6 = 330 OHMS, 1/4 watt 5%
R7,R8 = 22 OHMS, 5 WATT WIRE WOUND TYPE
C1,C2 = 470nF
T1,T2 = BC547,
T3,T4 = BD680, OR TIP127
T5,T6 = 2N3055,
D1,D2 = 1N5402
TRANSFORMER = 9-0-9V, 5 AMP
BATTERY = 12V,26AH,

Heatsink for the T3/T4, and T5/T6


Specifications:

  1. Power Output: 100 watts if single 2n3055 transistors are used on each channels.

  2. Frequency: 50 Hz, Square Wave,

  3. Input Voltage: 12V @ 5 Amps for 100 Watts,

  4. Output Volts: 220V or 120V(with some adjustments)

From the above discussion you might be feeling thoroughly enlightened regarding how to build these 7 simple inverter circuits, by configuring a given basic oscillator circuit with a BJT stage and a transformer, and by incorporating very ordinary parts which may be already existing with you or accessible by salvaging an old assembled PC board.

Need Help? Please send your queries through Comments for quick replies!




Comments

olupot said…
hello sir how can I intergrate Ics sg3524 and using ir2110 as a MOSFET driver thanks
Swag said…
yes that's possible
olupot said…
please help me with its circuit I want to setup one thanks
Carlos said…
Hello I want to know which of all the inverters published on this site is better for devices such as smart tv, led tv, pc, and notebook .. Thank you very much. From Buenos Aires Argentina.
Swag said…
yes it can be used for all SMPS based appliances.
Carlos said…
Hello, sir, thanks for the reply, but which one of all ...
Swag said…
All of them can be used.
Carlos said…
Thank you very much for your quick reply. My question is for the type of wave ... I just wanted to know if they are safe for last generation devices ... Thank you very much from Buenos Aires Argentina.
Swag said…
Any sinewave or modified sinewave inverter will be be good. But any 250V square wave inverter will also work because all the mentioned appliances are SMPS based and therefore will ultimately convert the AC into DC regardless of the waveform.
Carlos said…
Thank you very much for your quick reply. That's what I wanted to know. Thank you very much, you are a genius. Greetings from Buenos Aires, Argentina
Swag said…
You are most welcome Carlos!
Nkwenti said…
Sir.
Those are good and interesting projects and i must say that i appreciate it and all of your circuits have been working well with me and also improving on my studies...
but i must say i am sorry for asking this favor here....
Sir do you have any project for car theft?? i dont mean car alarm, if i set the gadget on, the car works on a timer, if someone takes off with the car, at certain distance the car automatically stop moving such like engine gets stoped or battery cutts off, if also a schematic that can work like GSM will also be appreciated...
thanks for understanding and i will be looking forward to be reading from you again.
Nkwenti.
Swag said…
Hi Nkwenti, GSM may not be required for this simple application, it can be done with a small timer circuit integrated with the ignition system. However how do you expect the theft to happen, is it by manipulating the ignition wires or by stealing the ignition keys or through duplicating the keys..because the circuit design will depend on how it is triggered.
Nkwenti said…
Sir can i replace the 2n3055 with TIP142?
Swag said…
TIP142 is a Darlington transistor so I am not sure how it might react, but there's no harm in trying. I would recommend TIP35 instead
nkwenti said…
Sir all i wanted was a simple schematic that can be adjusted to indicate car speed step by step and then from that step by step i can do additions to it to stop or quench the car engine... where i am i do not fine audinor's so a schematic that is not that complicated is what i am seeking for.
thanks for your reply sir.
nkwenti said…
ok sir... i will try TIP35 and also the darlington and give you my feedback... thanks for your help and guide... youre truly a teacher.
Swag said…
you are welcome nkwenti!
Swag said…
nkwenti, please type tachometer in the search box on top right you will be able to find the required design.
Nkwenti said…
you also sir.... well the reason why i ask if i can use TIP35 was because i came accros this circuit from a website which had your labels so is this a good working circuit? then i was wondering why 3kva will run only with 12vdc instead of at least 24vdc.
here is the link.

2.bp.blogspot.com/-OV6ZWLz_JW0/UmjW3hdGB6I/AAAAAAAAFjk/AQTrzhS3gGE/s1600/3kva+inverter+circuit.png
Swag said…
This circuit was copied by many other websites. You can find this circuit and even better ones under this category:

https://www.homemade-circuits.com/category/dc-to-ac-power-converters/

it is a good circuit but won't produce perfect sine wave, to get perfect sinewave you will SPWM instead of normal PWM.

output wattage depends on the battery specs, transformer specs and mosfet specs.....which can be easily modified and upgraded as per user preference.
Mark said…
Mr swagatam. Good day.. let me ask you again. I have inverter refrigerator but the board is dead. Can I direct it by using a simple circuit design? The main supply is 230 single phase AC mains and the output is 330 dc 3 phase. Thanks mr Swagatam.
Swag said…
Hello mark, do you want to discard the existing board and replace it with a new circuit? In that case you can specify the remaining things from the inverter which you want to include in the system, and specify their specifications, I may try to help!
Paaker said…
Hi Swag,

aim looking for a 12v to 19.5 3.5A DC Dc inverter. do you have it any such in inverter circuit?

Regards.
Jindro said…
Sir good morning!! can i use 1 amp trafo and smaller transistor like tip 31? ill use it with 3 to 7 watt bulb.
Swag said…
Hi Jindro, yes you can do that...
Swag said…
Hi Paaker, you can try the following concept

https://www.homemade-circuits.com/12v-car-laptop-charger-circuit-using/
Paaker said…
Thanks Swag. this is what aim looking for.
by the way this circuit aim going to power up a LCD TV not for charger. it can be use as power supply TV right?

Regards.
Swag said…
Hi Paker, yes it can be used for the said purpose, but the coil and the switching frequency will need to optimized correctly for getting the intended results.

The coil wire dimensions could be modified for achieving higher current outputs.
Akinbi Oluwadamilare said…
Helo sir, pls I need more light on inverter transformer winding...
Am just confused...
I want to know how to wind inverters transformer of different capacities.
But my concern now is how to choose or know the :
=> swg for any inverter transformer capacity.
=>size of lamination core ,
=>related calculation for each capacity before winding...
=> how to know or determine the required voltage at the primary like 230,220 volt etc
I want to do inverter of different capacities and I don't want to make mistakes with the transformer winding...
Swag said…
Hello Akinbi,

you can refer to the following article:

https://www.homemade-circuits.com/how-to-design-your-own-inverter/

although the max capacity will be 10 amps only.

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