This is the schematic diagram of simple 5W inverter circuit for Neon bulb. The inverter will convert the DC current (from battery) into AC current, from 12V DC to 220V AC with output power approximately 5 Watt.
This is the schematic diagram of 25W small inverter circuit. The inverter applies only 9 parts and turns 10 to 16VDC into 115VAC with square wave frequency of 60Hz to operate AC equipment approximately 25W.
The following image is the schematic diagram of 1000W power inverter circuit:
The circuit is based RFP50N06 MOSFET, converting 12VDC battery to become 110V or 220V AC voltage depended to the transformer used in the circuit. This inverter circuit produces stable square wave at 60Hz. Recommended IC1 is LT1013 which offers better drive, but you may use LM358. The heatsink should be use for the MOSFET.