ince the 1950’s there has been a great upsurge in the development, production and applications of semiconductor devices. Today there are well over 100 million semiconductor devices manu- factured in a year. These figures alone indicate how important semiconductor devices have become to the electrical industry. In fact, the present day advancement in technology is largely
attributed to the widespread use of semiconductor devices in the commercial and industrial fields.
One major field of application of semiconductor devices in the recent years has been to control large blocks of power flow in a system. This has led to the development of a new branch of engineer- ing called power electronics. The purpose of this chapter is to acquaint the readers with some impor- tant switching devices much used in power electronics.