I'm using a 100 Watt power transistor now. I'm getting closer to my goal.
I've attempted to transform up from 12 volts dc up to 120 volts ac.
I'm getting closer. I have caused 50 watt household bulbs to glow etc, with a relay. But the relay is kind of slow, it can't do 60 Hz.

I switched to transistors instead of a relay. My main problem is I have a little trouble with what impedence is presented by the transformer. I've ran a 120 volt ac radio on it. But some thing happened to the 2N3055. Could have been to much voltage on the base. A 50 Watt light bulb just gets 5 Watts. As the load increases, the circuit performance falls off. I'd could get by with 30 Watts of power for now. The transformer is capable of delivering 50 Watts as when 120 vac steped down was placed on it it fully illuminated the bulb.

The power transistor is strange, I'm not familiar with having amps go threw it.
Thats the third transistor I've burnt out. I'm not shure why its getting damaged. I do run a fan over it. Could be to much current into the collector,
when i turn the base voltage to high. Or it could just be base voltage above the 6 volt absolute maxinum rating.

Any idea about how to turn a 60 Hz 5 volt square wave into a 5 volt sine wave. Cascaded low pass filters, plus amplifier?