12vdc to 220vac inverter with pic 16f873

Hi! I am an amateur user of pic microcontrollers and I want to make a pure sine inverter 12v to 220v 50Hz and the output will be 200-300W. I must use pic16f873.Could someone help me with a schematic of the circuit I want to make please???Sorry for my english....

There are two methods for doin this
-- invert 12VDC to 12VAC then use a step up transformer
-- use a converter to raise the voltage upto 300VDC then invert

which one you want to use

the first method you said uses pic m/c?Do you have any schematic?

Added after 36 minutes:

My teacher also told me if I could make an inverter without transformer?He also told me that using PWM of pic16fxx I could make a sine Voltage using a lot of square pulses.

It's true that using PWM or a DAC you can make almost any waveform but have you consider that the maximum voltage you can produce from a 16F877 is 5V and without other circuitry, the maximum power it can produce is less than 1 Watt.

You don't have many options and none are very efficient unless you use a transformer:

Generate a square wave (you don't really need a PIC for that) at 12V and feed it to a voltage multiplier to step it up using a diode multiplier. Then take the output from a H-bridge configuration to allow the polarity to be reversed. You will have to use diodes with very low forward voltage drop at >20A forward current and they are hard to find. You may be able to find a Germanium type that can do it, good luck trying.

There are variations on that theme but all have the same problem of generating enough voltage. The idea of using a transformer is that you convert the power from low voltage to high voltage by converting high current to low current. I can't think of any other way of doing it efficiently at 300W load. Using the method I mentioned earlier, I expect efficiency to be less than 10% if it worked at all.

Brian.

Ok I can't find either informations without transformer.Is there any inverter circuit with schematic using any pic of 16f series with pwm method (with transformer)?