Showing posts from February, 2019


THYRISTOR Introduction Ample pioneering work on theory and fabrication of the power-switching device, which later came to be known as a thyristor (because its characteristics are similar to those of the gas-tube thyratron), was done at the Bell Laboratories in the U.S.A. The first prototype was introduced by the General Electric Company (USA) in 1957. Since then, many improvements have been made, both in the technique of its fabrication and in adapting it to numerous industrial applications. With the development of a number of other devices of similar type and characteristic, the whole family of such power-switching devices has come to be known as "thyristors". Since, the basic semiconductor material used for the device is silicon, it is also designated ao a silicon-controlled rectifier (SCR). The term SCR is often used for the oldest member of the thyristor family which is the most widely used power-switching device.
         The rating of SCR has been very much improved s…


ThyratronThyratrons are fast acting high voltage switches suitable for a variety of applications including radar, laser and scientific use. Perkin Elmer’s thyratrons are constructed of ceramic and metal for strength and long life. Over 300 thyratron types are available from Perkin Elmer. The types listed in this guide are a cross section of the broad line available. We encourage inquiries for thyratrons to suit your particular application. construction :
A thyratron (a hot - cathode gas field triode) consists of the following components :
1. plate : It is a disc of graphite.  2. Grid : It is a cylinder having diaphragm with one or more holes in it. The grid separates the cathode and the plate.  3. Cathode : A special construction oxide coated cathode is used so that its surface is not damaged due to bombardment of positively charged particles.                                                    Normally, a thyratron is filled with a small amount of inert gas such as argon, hydrogen, neon…