SE372660

A thyristor wherein a groove is positioned in a base between an auxiliary emitter and a main emitter. The groove causes an increased resistance for current flowing parallel to the upper pn junction when breakover triggering is initiated. Thus, the voltage drops at the pn junction of the auxiliary thyristor so that it is triggered while the voltage at the pn junction of the main thyristor remains below its gating voltage. The load current of the auxiliary thyristor forms a relatively high triggering or gating current for the main thyristor causing it to trigger linearly and/or laminar-like. The auxiliary thyristor is protected from high specific stresses by a fast current transfer onto the main thyristor.