I am making a simple inverter using the circuit below. I am using a 3amp 12-0-12 Transformer. I am aware of the cons of the circuit. So, I never expected regulated Pure Sine Wave output from it. The circuit works fine. But I am able to lit up a 5 Watt CFL Lamp only. I was trying to lit 10 or 15 Watt CFLs, but they didn't work.
How can I increase the output power of the inverter? Should I reduce R3 and R4? I guess, 3 amp Trafo is good enough for my expectation.
And I never saw the LED to lit up. If someone could explain the purpose of the LED and what changes would lit it up, it would be great.
Best Answer
In all probability you have insufficient voltage on the output to run your CFLs.
You are driving the 12-0-12 transformer with a 12 V square wave. That is giving you approximately a 228 V square wave on the output side. The domestic 230 VAC used to power a load is about 322 volts peak and since almost universally there is a bridge rectifier in the circuit of the CFLs they are designed to run from the peak voltage and not the RMS.
You have IMO two choices (and I'm only suggesting this for driving CFLs!!!!):
1) Increase you your input voltage. The turns ratio for your transformer is about 19:1 so to get closer to the 300 V peak you'd need about 17 VDC. You could use a boost convertor to provide this from your 12 V battery.
2) Change your transformer, which may be harder. You'd need about a 9-0-9 volt transformer.
Note.... big red flashing light ......you are setting the output voltage to 300 V RMS by implementing either of these solutions, so don't try to power anything other than the CFLs (or LED 230 VAC lights) https://en.wikipedia.org/wiki/Root_mean_square