This be power inverter circuit 120 Watt sizes that me use old electronic part all. It is make economize good. It can modify from voltage 12V of battery be electric house voltage 220V 50Hz cycle get. Which it uses power electric be 120 Watt apply to electric small-sized appliances such as television, tape radio , CD player , and other get. By it uses number base be number BC557 , TIP42 and 2N3055 etc. Which seek buy good easy , electronic part that important be transformer 12V CT 12V to 220V sizes 3A low like.