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How to make inverter circuit diagram within 5 minutes

When we need to use an inverter circuit diagram. Sometimes we cannot find it. But here is how to make inverter circuit within 5 minutes. In two simple inverter schematic diagram below. Just using two transistors, two resistors, and one transformer only. They can convert a battery 12v DC to 220VAC/120VAC to apply a small light bulb or a maximum 10 watts lamp.

They include two circuit ideas
1. Very Simple Inverter circuit using MJ2955 (PNP transistors)
2. Micro Inverter circuit diagram using TIP41 or 2N6121 ( Chayapol made its small size)

Very Simple Inverter circuit diagram using MJ2955

This is a simple inverter schematic diagram. I need to use a small light bulb at outdoor. Which it is no electricity, 220VAC.

My friend borrows mine 150 watts inverter. Which I used it in the car. It does works so well. So I do not have an inverter. Thus I need to build a new inverter in a hurry.

The main idea of the inverter circuit diagram

In this case, I do not need a high power and a long time using. Because I use the power of 10 watts for just a brief moment (30 minutes approximately).

Then, I look for all the parts in my store.  I have a lot of MJ2955 power transistors.

Thus, I choose an inverter circuit diagram like Figure 1.  It is so easy. It two MJ2955, two 68 ohms resistors, and one transformer only.
You see really it is possible!

Very simple 50 watt inverter using MJ2955

The  MJ2955 inverter circuit diagram

Both transistors and two resistors are set in an astable multivibrator mode.  The power transistors drive the transformer. It converts DC pulse to AC high voltage.

Which it looks like a below inverter. But it uses PNP transistor and high power than one.

My friend that is a guru about power electrical tells me.  This circuit style will not have capacitors. But it can generate the frequency.   The transformer secondary works as a load that can transform electrical to high voltage, in this case, is 220V but not sure is 50Hz.

However, the frequency output does not need to use with the load.

Let’s build this circuit.

This circuit is very simple but tiny size. I assemble them on the heatsink and connects all wires as Figure in the video below.


As video I use 12V battery 2.5Ah size as a source, secondly, I measure output AC voltage is 225-volts. Next, I apply lamps to the circuit. The voltage lower to 190-volts and can keep up power.

Figure 2 Application this projects.

The parts you need
Q1,Q2—MJ2955 or TIP2955 PNP power transistors = 2 Pcs.
R1,R2—68 ohms 2watts to 5 watts resistors = 2 pcs.
T1—12V CT 12V / 220V or 110V transformer = 1 pcs.
If you want 20 watts output, use 1A transformer.
Heatsink, 12V battery, etc.

Also, You may use the project below it looks great.

Micro Inverter circuit diagram using TIP41 or 2N6121

This circuit looks like above tiny inverter circuit above. Also, It converts 12V battery to ACV in range of 180V to 220V. At the output frequencies from 30Hz up to 65 Hz.

You can use it to general appliances under 10 watts. For example, Small fluorescent light bulb, LED lamps, timers, etc.

The LED save energy than fluorescent light bulb at same the lightness.

Also, this micro inverter circuit uses a normal transformer and dual NPN transistor. In assembling the circuit you just wiring the parts together by a leg to leg only. You may take about 5 minutes only to finish this circuit.

Note: Please read “Testing/application” below for real application.

Description circuit

The general inverter circuit uses an oscillator to drive a transformer with a power transistor.

Using dual transistors is push-pull switching, alternately works ON and OFF. Both transistors should have similar in a gain rate. But do not need the same.
How it works
When enter the power to the circuit. Either transistor will saturate (closed circuit) faster than one.

Suppose Q1 has closed the circuit first. The collector current of Q1, so it creates a magnetic field in the coil L2. Then, it gets more base voltage through R1. Q1 so quickly into a state of a closed circuit. Also, it makes Q2 is an opened circuit.

Micro Inverter circuit diagram using TIP41 or 2N6121
The micro inverter schematic diagram

The condition is like this until the transformer core reaches saturation point. Thus, the current flows to R1 reduce until cannot make Q1 in closed circuit status. The Q1 is the opened circuit.

In opposite, while Q1 is slowly changing from the closed circuit into opened circuit status. Q2 will begin to conduct more currents. The current will flow through R2 to increase a bias current to Q2. It makes Q2 to be closed circuit quick.

Now, the current of the battery will flow to coil L1 in a reverse direction. It causes the voltage induction to be the opposite polarity in the secondary coil of a transformer.
The Q2 will still conduct current until the transformer core reaches saturation.

After that, this process of the closed-opened circuit between Q1 and Q2, will be the same again. As long as, DCV is fed into the circuit

The capacitor across primary of transformer makes the output AC voltage to be smoothed or low noise.

How to make inverter

For in the project, use a few components. So It has how wiring circuit below, without PCB layout. I suggest some making techniques, as follows.

Wiring of micro inverter circuit
The wiring of this project

1. Use a mica insulator insert between case and body of the transistor. Then, use a plastic insulator. Next, hold the transistor body with hex nut and metal screw, as the figure below.

Mountiong the transistor on heatsink
The mounting the transistor on heatsink

2. Remember! Do not any lead of transistor touch to a case or short circuit between these lead.
3. Use ohmmeter check short circuit of various devices does not short circuit to a case as below.

Check short circuit with a multimeter

I test working as follows step:

1. Get the 12V battery, 2.5Ah. Or 12VDC regulated power supply, the current is more than 2A for testing.
2. Use AC volts meter to measure by setting 500 VAC range or AC volts digital meter like I use.
3. Apply the 12 V battery to this project.
4. Measure the output voltage. You should read voltage between 220V to 330V.

After that, try to use this inverter circuit project to load, 3 watts LED lamp. Because of Low power consumption.

This circuit has the output power about 5 watts to 10 watts only.

As above video, LED lamp glows brightly for 3 hours. Because it uses 0.5A only.

I assemble parts include 2 x TIP41 with the heatsink, 1K-resistors on the universal PCB board.

Note: Since, I have limit parts so use near parts only. I use 0.75A, 9V CT 9V transformer and two pcs of TIP41.

If you want to use higher watts. You can change some parts.

In the event of adding power is 20 watts. It requires the transformer that provides the current over than 2A and changes R1 and R2 are 100 ohms 5W instead.

Components list
Q1, Q2—TIP41 or 2N6121, transistor NPN 40W 45V 4A
LED1—Red LED or as you need.
Resistors (0.5W +/- 5% Carbon)
R1, R2—1K
C1—0.1uF 630V, mylar capacitor
T1—Transformer 220 VAC primary coil/10-0-10V, 750 mA- secondary coil
F1—Fuse- 0.5 A
SW1—Toggle switch
AC- plug, mica insulator, LED, plastics, 12 VDC Battery, solid Wires no. 20 AWG length 1 feet, nut and screw, etc.

This Post Has 62 Comments

  1. How much AMP transformer required for this inverter?

    #Micro Inverter using TIP41 or 2N6121

  2. can i use tip41 for the transistor?

  3. i think we use 20v tapped transformer

  4. can i use mje3055t in place of Q 2n6121

  5. i have made this circuit. i hav used 12-0-12V transformer with a rating of 2A.when i give a supply of 12V input, the LED glows but the transistor Q2 gets heated up. but still i am unable to get the output. can anybody help me??

  6. i didnt get the transistor 2N6121. so instead of it, i am using its equivalent transistor D1274.

  7. Bonjour j’aimérais si possible de savoir quel son les transisteurs qu’il faut metre pour haugementer la puissance de cette inverter

  8. what is it power and how much load it can bear.
    please help me

  9. Hi,Aziz

    It can use for 10-30watts load power.

  10. i did’nt get the output plz help me

  11. I love your site. Its interesting

  12. can i use npn 2n3055 or tip3055 instead of pnp mj2955 please help me.

  13. I think in this diagram drew somthing wrong. is this circuit draw correctly. please sir reply me soon bcoz i wanna build this circuit as soon as possible.

  14. I have already made your suggested circuit ‘micro-inverter-by-2n5121’ using D880, and it works successfully. And now my question is if I use TIP3055 or 2N3055 transistor than which resistor I use 1k or 68 ohom. Another request, can you give me the formula to choose right resistor for base bias. I mean which formula you use to choose 68 ohom for this circuit. Please sir help me.

  15. Here you use 12v-0-12v center tap transformer but how many amp would need to produce 50w output. Because in the diagram I saw only 1A rating. And so many thanks for reply my first question. This site is such a blessing for hobbiest like me.

  16. hi.,

    how can i add more transistors to make this support for higher loads., in what way., the add-on transistors should be connected.,

    can any body

  17. Hi,sumalatha.

    It not sure you should use correct size transformer and R1,R2 some time must be use lower than 1K at 5Watt.

    #Micro Inverter using TIP41 or 2N6121

  18. very helpful and informative

    #Micro Inverter using TIP41 or 2N6121

  19. Hi, Joel
    Thanks for your feedback.

    #Micro Inverter using TIP41 or 2N6121

  20. please how to modify the circuit to obtain the output power equal to 150 wattes i wont to realize it with 220V and 50Hz and 150W in output and thanx a lot

  21. o built this curcuit but the resistane start heated& then one of the tansistor get damage i will try this again…please help..

  22. Hi can this inverter circuit be used with a portable battery operated radio with rectifire of course

    #Micro Inverter using TIP41 or 2N6121

  23. Hi,hoang anh ky
    Thanks for your feedback.
    You can use about 2W to 5W or 10W.

  24. Can i use ordinary transformers? Primary winding is 220v and secondary 12 – 0 – 12

  25. HELLO admin,
    I have made this circuit with mje3055 and 68ohm/5w resistor. i connect emmiter to ground and transformer’s center to (+) because they are npn transistor but there is no output. both of the transistor got overheated though i use two big heat sinks seperately. but no output,where is the problem please help me sir please.

  26. yup i is a ordnary transformer 12-0-12 0 means centertap (CT)

  27. Hello Sir,
    i m making 50watt mj2955 inverter. In this inverter automatic charging system is available??

  28. please corect diagram.

  29. sir what is the use of mj2955 in the circuit ?

  30. dose it work in 5amp trasformer

  31. Hi good work. I will try

  32. How many amp transfor would I use in other to hv 50watt output

  33. not work huhu

  34. not work..huhu

  35. i wanna know how to make a simple inverter

  36. Hi
    can you send your circuits to me
    on my mail

  37. Sir I made that inverter but its not working I m worried help on proper way .

  38. Can i use 5amp transformer

  39. Hi,
    did anyone get this circuit to work?
    The LED comes on, the TIP 41`s over heat and there is no output

    #Micro Inverter using TIP41 or 2N6121

  40. Hi Des,
    Thanks your feedback.
    This circuit works please check connection of TIP41’s legs.

    #Micro Inverter using TIP41 or 2N6121

  41. Hey sir , I saw this diagram its very simple ckt for built a inverter .
    But Can u tell me this ckt diagram is accurate? Coz, its look like a very easy ckt. And somwone also reqyested to u to corrcect this diagram .
    I want a built a inverter.
    I am very thankful if u give reply of my request.

  42. 2. 12V to 220V Inverter 180W by 2N3055

    if i use 12 v and 7.5 A battery THEN IS THERE ANY PROBLEM

  43. Hi

    I need a circuit to convert 5V 2A DC to 12V 0.5A AC supply for powering my dlink router from
    usb powerbanks . Please help me to figure it out.

  44. Please, i will need a live working complete circuit diagram foe a 1KVA Power Inverter using MOSFET technology and a 12V battery. I will be very grateful for your timely assistance.

  45. Sir thank you for this circuit it work real good, am a student of electronics engineering who look forward to communicate with you personally on some circuit thank you.

    #Micro Inverter using TIP41 or 2N6121

  46. hi I need to know what would happen if my battery tuns low up to around 7volts eould the simple 2N3055 inverter still work????

  47. I am interested in your circuits

  48. can i use it for long time? approx. 5 hours

  49. Hello sir my ckt was not working I use component 12-012transformer
    mj2955 transistor
    .68ohm 5watt resistor

  50. Sir plz help me,ac voltage get at point below center tap transformer and its value is 15v Ac but transformer couldn’t get step up into 220v,transformer get heat but didn’t give any output.. What is problem in it?… Also how much Ah of battery can I use?

    #Micro Inverter using TIP41 or 2N6121

  51. Hai sir, I am a engineering student. I have seen your simple inverter model using mj2955. It was fabulous. So I want to know detail study about it and how it is working. Can you help me

  52. please Sir can I use 0.1uf carpastor 50v

    #Micro Inverter using TIP41 or 2N6121

    1. No, you cannot use it. Because of the low voltage rate. You need more 400V.
      But sometimes you may not use that capacitor. Try it first. Have a good day!

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