What is the structure of a thyristor?

The thyristor has three poles-anode (A), cathode (C) and control pole (G). The die is a four-layer structure composed of a P-type conductor and an N-type conductor. There are three PN junctions in total. It is very different in structure from a silicon rectifier diode with only one PN junction. The four-layer structure of thyristor and the introduction of the control electrode laid the foundation for its excellent control characteristics of “controlling big by small”. In the application of thyristor, as long as a small current or voltage is added to the control electrode, a large anode current or voltage can be controlled. At present, SCR components with current capacity of several hundred amperes or even thousands of amperes can be manufactured. Generally, SCRs below 5 amperes are called low-power SCRs, and SCRs above 50 amperes are called high-power SCRs.