Simple tested circuit to convert 12v DC to 220v AC using transistors,MOSFET and another circuit using 555 is explained here.
Dual Power Supply Circuit Diagram - 230VAC to ±12VDC
7 Simple Inverter Circuits for Newcomers
Square wave Inverter Circuit - Gadgetronicx
12V DC to 220V AC Inverter Circuit & PCB
How to make 200 Watt Inverter
3 Best Transformerless Inverter Circuits - Homemade Circuit Projects
7 Simple Inverter Circuits you can Build at Home - Homemade Circuit Projects
12v DC to 220v AC Converter ( INVERTER ) - No Transformer, No Resistor, No IC
How to make simple inverter circuit diagram within 5 minutes
18W Mini Inverter (12v DC to 220v AC)
Simple Inverter 12v DC to 220v AC, Converter project for Car & Home
How to Make 12V DC to 220V AC Inverter : 4 Steps (with Pictures) - Instructables
12V to 230V Inverter Circuit Diagram using 555 timer IC » Inverters
Inverter 12V DC to 240V DC - Schematic Design