Attention: This Circuit is using high voltage that is lethal. Please take appropriate precautions
This circuit you can convert the 12VDC into 220VAC. The 4047 IC is use to generate the square wave of 50hz.
How to calculate transformer rating
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 18.3A at 12V because: 12V*18.3A = 220V*1A, when P1 is 12V*18.3A and P2 is 220V*1A.
So if you have to wind the step up transformer 12V to 220v but input winding must be capable to bear 20A.
For this project to produce 220VAC with 500W, we find.
Output power is P2 = Output voltage x output current
Output current = 500W/220V
= +- 2.272A
most importance is primary current
P1 = 12V x current
500W = 12V x current (I1)
I1 = 500W/12V
So your transformer to must be capatable to support primary current at lease 41.67A and don't forget for 2N3055 max current 15A . At lease 4 pcs for both side, total 8 pcs of 2N3055.