Here simple 20 Watt – 40 Watt inverter circuit diagram which able to convert 12V DC become 110V or 220V AC.

Tips :

First wire to oscillator part only.
Then check out put Pin 10 &11 of CD4047 to obtain the required wave forms ( two 120Hz ,180 degree out of phase,50% duty cycle waves.
Then connect transistors ,transformer and load (25 W bulb for test).See it working!.

A transformer can be viewed as a converter that can increase voltage and lower current, or vice versa. It only works when using AC.

The transformer is effectively a magnetic circuit. The transformer has two or more coils of wire wrapped about a common core.

The ideal relationship is: