thyristors

The thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as a switch, conducting when their gate receives a current pulse, and continue to conduct for as long as they are forward biased.Some sources define silicon controlled rectifiers and thyristors as synonymous; others define SCRs as a subset of thyristors, along with gate turn-off thyristor (GTO), triode ac switch (triac), static induction transistor (SIT), static induction thyristor (SITH) and MOS-controlled thyristor (MCT). Among the latter, the International Electrotechnical Commission 60747-6 standard stands out.
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TIRISTORI