The SIDAC is a silicon bilateral voltage triggered switch. 
Upon application of a voltage exceeding the SIDAC breakover
voltage point, the SIDAC switches on through a negative 
resistance region to a low on-state voltage. Conduction 
continues until the current is interrupted or drops below the 
minimum holding current of the device.
SIDACs feature glass-passivated junctions to ensure a 
rugged and dependable device capable of withstanding 
harsh environments.