SCR (Silicon Controlled Rectifier)

A semiconductor device that functions as an electrically controlled switch for DC loads. The SCR is one type of thyristor.

A semiconductor device used to provide stepless control of an electric power circuit without the necessity of load matching; usually, two rectifiers are used in the circuit to provide full-wave control of the heater element, but in some instances two SCRs are used in a single package, know as a triac.