I'm looking for a simple type of component that I can put in a basic circuit, that will complete and break the circuit many times real fast. Probably between about 10-30 times a second. The current would be from either a AA or 9 volt battery. Is there any type of basic component, or simple circuit that will let the full current from a AA or 9 volt through in pulses, about 10-30 pulses a second? Perhaps a way to adjust the pulse rate too? thanks.