Thyristors or silicon controlled rectifiers (SCR) as they are sometimes known may appear to be unusual electronics components in many ways, but they are particularly useful for controlling power circuits. As such these electronics components are often used for applications such as light dimmers, and there may be thyristor circuits used in many power supply applications. Thyristors are simple to use and cheap to buy and often thyristor circuits are easy to build and use. All these reasons make thyristors ideal components to consider for many applications.
The idea for the thyristor is not new. The idea for the device was first put forward in 1950 by William Shockley, one of the inventors of the transistor. Although some later investigation of the device was undertaken by others a couple of years later, it was not until the early 1960s when they became available. After the introduction of the thyristor, they soon became popular for power supply circuits