Note18-Feb-16: Test your transformer before doing this project. ***The transformer in the pic is a custom made (48V center tapped / 220v ) 2000 watts, weights like 10 kilos. **You can make the secondary 110v if needed. 2> If you increase the power transistors you have to enlarge the T2 transformer to match the new needs, the circuit's transformer is rated 25 amps to handle 250 watts of 220v, for every 1 additional amp you need on the 220v side you have to increase 10 amps on the 12v side, of course there are limits to the thickness of the winding so if you need more than 750 watts i recommend that you use a 24VDC supply instead of 12 volts: DC voltage and Transformer 'T2' size recommendation: (Power) ( Supply) ( Transformer Winding) (750w) (12VDC) (P:24V '12-0-12' / S:220V) (1500w) (24VDC) (P:48V '24-0-24' / S:220V) (2250w) (36VDC) (P:72V '36-0-36' / S:220V) (3000w) (48VDC) (P:96V '48-0-48' / S:220V) (3750w) (60VDC) (P:120V '60-0-60' / S:220V) (4500w) (72VDC) (P:144V '72-0-72' / S:220V) (5250w) (84VDC) (P:168V '84-0-84' / S:220V) *The transformer should be 'center tapped' at the primary side. Notes: 1> The schematic circuit design is for a 250 watt output, while the pics are of my 1500 watts inverter that i built, to increase the power of the circuit you have to add more of the Q7 and Q8 transistors in parallel, each pair you add will increase your power by 250 watts, ex: to get 750 watts of power from the inverter you need to add in parallel 2 of Q7 and 2 of Q8 to the original design. If you like the work and intend to build the circuit don't forget to click on the 'I made it' button so I know how many people benefit from the design, Thanks.

I've been using it as a backup to power up all my house when outages occur since aprox. This is a heavy duty design of a Pulse Width Modulator DC/AC inverter using the chip SG3524.

12 volt to 220 volt inverter 5000w