In the process of thyristor operation, its anode (A) and cathode (K) are connected with power supply and load to form the main circuit of thyristor, and the gate G and cathode K of thyristor are connected with the device of thyristor control to form the control circuit of thyristor.
Thyristor is a semi-controlled power electronic device. Its working conditions are as follows:
1. When the thyristor withstands the reverse anode voltage, the thyristor is in the reverse blocking state regardless of the gate voltage.
2. When the thyristor is subjected to positive anode voltage, the thyristor is turned on only when the gate is subjected to positive anode voltage. At this time, the thyristor is in the FORWARD-CONDUCTING state, which is the thyristor's thyristor characteristics, which can be controlled.
3. When the thyristor is on, as long as there is a certain positive anode voltage, regardless of the gate voltage, the thyristor will remain on, that is, the gate will lose its function after the thyristor is on. The gate pole only acts as a trigger.
4. When the thyristor is on, when the voltage (or current) of the main circuit is reduced to near zero, the thyristor is turned off.