Power Electronics Devices, Circuits and Industrial Applications

V. R. MOORTHI

Preference :

Power electronics is a branch of engineering that combines the fields of electrical power, electronics, and control. It started with the introduction of the mercury arc rectifier in 1900. The grid controlled vacuum tube rectifier, ignition, and thyratron followed later. These found extensive applications in industrial power control till 1950. In the meanwhile, the invention of the transistor—semiconductor device— in 1948 marked a revolution in the field of electronics. It also paved the way for the introduction of the silicon controlled rectifier (SCR), which was announced in 1957 by the General Electric Company. In due course, it has come to be named as the ‘thyristor’. There is one important difference between the earlier electronic tubes and their semiconductor successors. On the low-current side, the transistor is a base current controlled device whereas its predecessor, the vacuum tube, is a grid voltage controlled device. Similarly, the thyristor, which is designed to carry high currents, is a gate current-controlled device; it has succeeded the thyratron, which is a grid voltage-controlled gas tube.