More information would help. Things like the voltage and current you want to switch? The application? A detailed explanation? You have not provided any information. The light switches in my house are power switching circuits.
30 volts @ 10 amps use a relay, SSR or contactor. AC to AC I can understand but AC to DC? Are you talking about designing and building a SMPS as in Switch Mode Power Supply? A power supply that runs on AC and provides DC? What are you trying to do?