Electronic Circuits and Diagram-Electronics Projects and Design

Comparison of  Thyristor and Transistor As already mentioned, transistors and thyristors are both semiconductor devices. They are now widely employed in switching operations because of their numerous advantages such as noiseless operation owing to absence of moving parts, very high switching speed (say 109 operations per second), high efficiency, low maintenance, small size, little weight and trouble free service for long period, large control current range (say from 30 A to 100 A) with small gate current of few mA over mechanical switches or electro-mechanical relays. However, transistors and thyristors both have their own areas of applications. Thyristors have some…

Comparison between Thyristors and Thyratrons Before the discovery of thyristors, thyratrons were used for industrial control, but now they have been replaced by the thyristors because of the following drawbacks of thyratrons. 1. Thyratron needs a large anode-to-cathode voltage and a separate filament supply whereas the thyristor needs only one main supply and a control signal. 2. Thyratron takes long time in ionising and deionising and, therefore, is unsuitable for higher frequencies (beyond 1 kHz). A thyristor can operate over a wide range of frequencies because it can withstand as high as 200 A/micro seconds rate of rise of current….

Thyristor Family-Types of Thyristors The P-N-P-N devices with zero, one or two gates constitute the basic thyristor. But today the thyristor family includes other similar multilayer devices also. The complete list of thyristor family members include diac (bidirectional diode thyristor), triac (bidirectional triode thyristor), SCR (silicon controlled rectifier), Shockley diode, SCS (silicon controlled switch), SBS (silicon bilateral switch), SUS (silicon unilateral switch) also known as com­plementary SCR or CSCR, LASCR (light activated SCR), LAS (light activated switch) and LASCS (light activated SCS). The most important member of the thyristor family is the silicon controlled rectifier (SCR). SCR is a four…