A Thyristor, also known as SCR or Silicon Controlled Rectifier is one of the important members of the electronic components family. These are semiconductor active electronic parts with specific functions and have numerous application areas with everyday electronic gadgets.
A Thyristor or SCR is a three terminal or “legged” electronic device or part which is designed to act like a switch for toggling power to a connected load in response to trigger signals applied to one of its terminals.
The following explanations provides some idea regarding how to use a SCR or a thyristor in electronic circuits.
Basically a SCR has
When the gate is triggered with a DC potential, the internal semiconductor switch “opens” and allows the load voltage from its anode to pass through its cathode into the ground, thus switching ON the load. The load remains switched ON as long as the DC level is maintained over the gate of the SCR and the load is deactivated once this trigger is inhibited from reaching the gate of the SCR.
However, unlike a Triac, an SCR will allow only one half cycle of the AC phase through it and therefore cannot be used for applications which require 360 degree control features of the connected equipment.