The main purpose of the thyristor in the circuit

Controlled rectification

The most basic use of ordinary thyristors is controlled rectification. The familiar diode rectifier circuit is an uncontrollable rectifier circuit. If the diode is replaced by a thyristor, it can form a controllable rectifier circuit, inverter, motor speed regulation, motor excitation, non-contact switch and automatic control. In electrical engineering, the half cycle of alternating current is often set as 180°, which is called electrical angle. In this way, in each positive half cycle of U2, the electrical angle experienced from the zero value to the moment of the trigger pulse is called the control angle α; the electrical angle at which the thyristor conducts in each positive half cycle is called the conduction angle θ. Obviously, both α and θ are used to indicate the conduction or blocking range of the thyristor during the half cycle of the forward voltage. By changing the control angle α or the conduction angle θ, the average value UL of the pulse DC voltage on the load is changed, and the controllable rectification is realized.

Contactless switch

The function of thyristor is not only to rectify, it can also be used as a contactless switch to quickly turn on or off the circuit, realize the inversion of direct current into alternating current, and change one frequency of alternating current into another frequency of alternating current ,and many more.