High speed solid-state switch

I need such a switch for a simple circuit that I am designing but it is a long time (40 years) since I have meddled with electronics, hence this question.

I believe that a power transistor will do the job, however I am not at all sure about how to set it up or what voltages etc. will be required. The switch should be able to handle voltages in either direction, to act like a circuit breaker.

There will need to be a mechanical switch involved to control the transistor (or whatever) and the latter would need to non-conducting in its normal Off state.

I will be using a prototyping board initially. The power supply will be a battery of some kind.

Apologies for the vagueness but this could be the subject of a patent so I don't want to give too much away in public.



Thanks ...

Richard

What voltages and currents do you need for the switch, AC or DC?