Vishay VS-30TPS12-M3, Thyristor 1200V, 20A 45mA

Thyristors - Vishay Semiconductor

A Thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased. Thyristors are synonymous to Silicon-Controlled Rectifier (SCR).
Encapsulated modules with electrically isolated base plate. Suitable for applications such as battery chargers, welders and plating equipment, regulated power supplies and temperature and speed control circuits.