Silicon Controlled Rectifier SCR component

The silicon controlled rectifier (SCR) acts as a switch, where it stays off, until it is given a strong enough positive signal to the gate to turn it on as long as the anode is more positive than the cathode. The SCR then stays on until power is cut from anode to cathode. The SCR does not conduct when the cathode is more positive than the anode no matter the gate signal.

MCR100 6G silicon controlled rectifiers SCR I use in my videos came from this kit.
Silicon Controlled Rectifier SCR component demonstration MCR100 6G