Reviving Silicon Controlled Rectifier Technology in Modern Times

An Electric Device from the Past Gains Attention

On YouTube, the channel [Lockdown Electronics] examines an older device known as the Silicon Controlled Rectifier (SCR). This invention dates back to the 1950s and was a popular type of thyristor in the 1970s. Although it is often replaced by TRIACs and MOSFETs today, older electrical schematics still call for its use, and SCRs remain available for purchase.

An SCR is a three-terminal electronic switch that stays activated. Once a signal is applied to the gate, the other two terminals, the anode and cathode, can conduct electricity and continue to do so until the power source is interrupted. The semiconductor structure inside the device consists of three semiconductor junctions, formed in a PNPN sequence. The left P represents the anode, the right N is the cathode, and the middle P on the right is the gate.

In the video, [Lockdown Electronics] explains how to use the SCR and compares it to the TRIAC. Unfortunately, the lighting is not optimal for demonstrating the SCR with alternating current. At the end of the video, [Lockdown Electronics] presents a circuit control for windshield wipers dating back to 1977, based on SCR technology. If you want to learn more about SCR technology, we have provided the essential information.