Power and Switching Devices

As already mentioned in Chapter 1 the term ‘thyristor’ is used for the family of semiconductor devices that exhibit bistable characteristics and can be switched on and off like the gas-tube thyratron. The SCR, which has been discussed in detail in Chapter 2, is a member of this family, and is widely used because of its large power-handling capacity. The operating characteristics of some of the other important thyristors are described in this chapter. All, except the triac, are low-power devices often used for switching in control circuits. They also find applications as efficient triggering devices for SCRs and triacs, and in digital and pulse circuits.