Excellent uni-directional switches for phase control applications such as heating and motor speed controls. Sensitive gate SCRs are easily triggered with microamperes of current. Standard phase control SCRs are triggered with few milliamperes of current at less than 1.5V potential.

Thyristors - Littelfuse

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).