Thyristor

A switching semiconductor device with three or more PN junctions. The most common type is a four-layer device consisting of alternating P-type and N-type materials, and it has three electrodes: anode (A), cathode (K), and gate (G). The on/off control between the anode and cathode can be achieved by the presence or absence of a small gate current. In addition, switching operation is possible by utilizing the characteristic that the device turns off when the current flowing to the anode falls below a certain value. Because it has a wide range of peak reverse current and average forward current, it can be used for high-voltage and high-current applications compared to the transistor, which is also a PN junction device. Applications include contactless switches and rectifying devices, as well as motor control, light dimming control, and temperature control of electric kotatsu and electric furnaces. Triacs (bidirectional three-terminal thyristors) and GTOs are also types of thyristors.