12V to 120V InverterHome > Circuits > Power Supply > 12VDC To 120VAC Inverter

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Have you ever wanted to run a TV, stereo or other appliance while on the road or camping? Well, this inverter should solve that problem. It takes 12 VDC and steps it up to 120 VAC. The wattage depends on which tansistors you use for Q1 and Q2, as well as how "big" a transformer you use for T1. The inverter can be constructed to supply anywhere from 1 to 1000 (1 KW) watts.

Important: If you have any questions or problems with the circuit, see the forum topic linked to in the Notes section. It will answer all your questions and provide links to many other (and better) inverter circuits.

Schematic

PartsPart Total Qty. Description Substitutions

C1, C2 2 68 uf, 25 V Tantalum CapacitorR1, R2 2 10 Ohm, 5 Watt ResistorR3, R4 2 180 Ohm, 1 Watt ResistorD1, D2 2 HEP 154 Silicon DiodeQ1, 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 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.

7. If you want to make 220/240 VAC instead of 120 VAC, you need a transformer with a 220/240 primary (used as the secondary in this circuit as the transformer is backwards) instead of the 120V unit specified here. The rest of the circuit stays the same. But it takes twice the current at 12V to produce 240V as it does 120V.

8. Check out this forum topic to answer many of the most commonly asked questions about this circuit: 12 - 120V Inverter Again. It covers the most common problems encountered and has some helpful suggestions.

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Add A Commentbosco 12VDC To 120VAC Inverter Monday, May 02, 2011 6:39:33 AM

iam a student of Busitema University, Uganda making a 12vdc to 120vac inverter but i have failed to get the centre tapped transformer and the tantulum capacitor. can some one help me if there are alternatives for these equipments. thanks

lars12VDC To 120VAC Inverter

PLEASE HELPTuesday, March 29, 2011 9:34:46

AMi have build this scheme but it doesn´t work.i have tried to reverse c1 and c2 but it will make no difference. when input is 12vdc, i wil measure on both collectorsides -12 vdc. i have connected a transformer, q1 and q2 will heating up (cables also) but there is no voltage on the secondaire side of the transformer. please help me and tell me wat i´m doing wrong.

anonymous 12VDC To 120VAC InverterSunday, March 20, 2011 10:06:56

PMi need a little clarification on the transformer from a microwave, 1) which one is primary and which is secondary? 2) are you saying get rid of the secondary windings all together and wind your own or wind a total of 24 more on top of the existing wings. thx for your help

anonymous 12VDC To 120VAC InverterSaturday, March 12, 2011 8:54:24

PMis this square, modified, or pure sine wave?

pradeep kr sahu 12VDC To 120VAC InverterFriday, February 25, 2011 1:44:21

AMi made this circkit, it works in good condition.but i don't know working principle/operation. my project prensentation is on 2nd march 2011 ,so plz anybody help me plzzzz....

anonymous 12VDC To 120VAC InverterThursday, February 03, 2011 9:22:24

PMinstead of a 2n3055 transistor, can i use a mosfets in the circuits? Thanks

anonymous 12VDC To 120VAC InverterSunday, January 23, 2011 1:55:33

PMAren't you giving less input and drawing more output from this circuit, in terms of power?

anonymous 12VDC To 120VAC InverterThursday, January 13, 2011 10:48:01

PMCar batteries are made for heavy discharge, but not for sustained discharge. You need AGM or deep cycle. Trojan 105 would work. They are 6V each, but a pair of them will out perform any

12v battery.

anonymous 12VDC To 120VAC InverterFriday, January 07, 2011 11:41:33

PMDear Robo Builder: D1,D2 and R1,R2 are for transient protection across the secondary of T1. The output waveform would approximate a square wave. Dear Simon: The output frequency is determined by those 68uF tantalum caps and it could be adjusted by changing the value of the caps.

P.Senthil kumaar 12VDC To 120VAC InverterWednesday, January 05, 2011

11:03:08 PMThe first part of two transistors are use to generate a pulses.This is known as astable vibrator. Use only a center tapped transformer and keep positive as constant in middle one.The the inverting input of negative charge is applied alternatively for other two ends. When diode is connected reversely in transformer to avoid the back emf to damage the transistor like a relay. If you want to change the frequency means simply change the value of the capacitor. NOTE: Higher frequency will damage the electrical applications. If any one have a personal question mail me at senolabled@gmail.com I'm your friend please ask frankly.....

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