The following diagram is the basic design diagram of inverter circuit. The circuit will convert 12V DC to 120V AC. This basic inverter circuit can handle up to 1000Watts supply depends the T1, T2 and transformer used. Please see the note.

Basic Inverter Components list:

Part Total Qty. Description Substitutions
C1, C2 2 68 uf, 25 V Tantalum Capacitor
R1, R2 2 10 Ohm, 5 Watt Resistor
R3, R4 2 180 Ohm, 1 Watt Resistor
D1, D2 2 HEP 154 Silicon Diode
Q1, Q2 2 2N3055 NPN Transistor (see “Notes”)
T1 1 24V, Center Tapped Transformer (see “Notes”)
MISC 1 Wire, Case, Receptical (For Output)

 

Notes:

1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.

2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055’s in the parts list can only handle 15 amps each.

3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Don’t let your battery go dead :-).

4. Since this basic inverter project produces 120 VAC, you must include a fuse and build the project in a case.

5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.

6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

circuit schematic

View Comments

  • A straightforward charger equivalent to a ACDC wall adapter. It applies 300mA to the battery pack in any respect times, which will harm the battery power if left connected as well extended.

  • Hello! I have the same problem as @karthik. Could you please provide use the equation. Thank you!

  • for the student frm edo state and all of you asking qustion on inverter, you can get theelectronics part from any radio/electronic accesory store. if u want higher kva for the inverter eg 5kva then you will have to connect 25 of those transitors in parrallel at each side to ake the total number of transistors 50, and then change the transformer to a large one, after which the total circuit will be powered with 36v. that is three 12v batteries connected in series. for more question contact me with my emial matamba2@googlemail.com. i will be willing to be of help.

  • sir,I have tested this circuit but the resistor 180 ohm is heated up very quickly,I would like to know the equation to calculate the values so that i can use different voltage levels as the input for your circuit.

  • Sir i want to design different types of invertors.Please send me circuit diagrams with compleat information about components.

    Highly obligued to you in anticipation.

  • Dear sir

    I want to make 12v dc to 240v ac,400 watts inverter.plz send the message which requirements i

    need and send me circuits and parts name in my mail address.

    Thanks&regards
    Ravindramohan.M

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