Thyristors
are solid state semiconductor devices. Thyristors have four layers of
alternating N and P type material. This enables thyristors to act as bistable
switches, they conduct when thier gate recieves a current pulse, and they
continue to conduct for as long as they are forward biased. Thyristors are
commonly employed when high currents and high voltages are used, and thyristors
are very often empoyed to regulate alternating currents. Thyristors are also
found in power supplies for digital circuits, where they are used as a circuit
breaker. Thyristors are used as control elements for triggered controllers, also
known as phase fired controllers. There are many types of thyristors of which
these are some: ASCR Asymmetrical SCR, GTO Gate Turn Off Thyristor, SITh Static
Induction Thyristor and IGCT Integrated Gate Commutated Thyristor.