Thread: Silicon-comtrolled rectifiers

SCRs can be seen as conventional rectifiers controlled by a logic gate Signal. These four-layered, three-terminal silicon rectifiers can e controlled through their gate terrrilital. Normally, an SCR acts as an 'open switch' and in the' off' state, the device
restricts current flow. When the gate-to-cathode voltage exceeds a certain threshold, the device turns on ana conducts current in the anode-cathode direction.



The SCR then 'self-latches' into .r on' state and stays' on' until the anode-to-cathode current falls point, the SCR turns off and again becomes an open switch.
In 'on' state, the SCR exhibits low impedance, which is maintained as long as the current in the terminals is above the holding current limit. In 'off' state, the SCR has high impedance, which is maintained as long as the applied voltage is below the 'break-over voltage.'