We found this circuit in the magazine Eletcronics Now of July 1994. The power supply is according to the relay and the transistor can be any general purpose one.
This circuit was obtained from a 2005 Linear Technology application manual. The circuit is...
Small time intervals up o some minutes can be achieved with this circuit. Only incandescent lamps...
This circuit is from a 1977 Radio Shack documentation. It produces a modulated sound of good...