Introduction to turn-off silicon-controlled rectifiers

The term “turn-off silicon-controlled rectifier” relates to a 4-layer p-n-p-n switch, which can be turned on and off by gate current pulses of opposite polarities. Conditions for gate turn-off are analyzed by the carrier charge concept. Two methods for obtaining gate turn-off are developed and experimentally verified. Turn-off current gains of 1,000, and more, were measured. An estimate is made regarding larger turn-off SCRs (silicon-controlled rectifiers) of the future, and some applications are listed.