Silicon Controlled Rectifier (SCR)
- SCR is one of the oldest types of solid state power device. It was invented in 1957 by the General Electric Research Laboratories.
- SCRs have the highest power handling capacity of all the power semiconductor devices. They have a four layer construction with three user accessible terminals namely anode, cathode and gate.
- SCR is a latching type device that can be turned on by the control terminal (gate) but once turned on, the gate loses control it (i.e. it cannot be turned off by the gate).
Important Features of SCR
- It is a latching type device.
- It can handle a very large power.
- It is a current controlled device, because the gate current controls SCR.
- It acts as an open or closed switch but it can not be used as an amplifier.
- The on state voltage drop is very low.
- It can handle thousands of amperes of current.