Transistored Power Inverter 400W. The basic formula is P=VI and between input output of the transformer we have Power input = Power output. For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18.3 = 220v*1 . So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.
