1. Choose the type of thyristor
There are many types of thyristor, which should be selected reasonably according to the specific requirements of the application circuit.
If it is used for AC and DC voltage control, controllable rectification, AC voltage regulation, inverter power supply, switching power supply protection circuit, etc., an ordinary thyristor can be used.
If it is used in AC switches, AC voltage regulation, AC motor linear speed regulation, lamps linear dimming and solid-state relays, solid-state contactors, and other circuits, the triac should be used.
If it is used for variable frequency speed regulation of AC motor, chopper, inverter power supply, various electronic switch circuits, etc., the gate turn-off thyristor can be selected.
If it is used for sawtooth wave generator, long time delay device, overvoltage protector and high-power transistor trigger circuit, etc., BTG thyristor can be selected
If it is used in circuits such as electromagnetic cookers, electronic ballasts, ultrasonic circuits, superconducting magnetic energy storage systems, and switching power supplies, reverse conducting thyristors can be selected.
If it is used in photocoupler, photodetector, photoalarm, photocounter, photoelectric logic circuit, and operation monitoring circuit of the automatic production line, photocontrolled thyristor can be selected.
2. Selecting the main parameters of the thyristor should be determined according to the specific requirements of the application circuit.
The elected thyristor should have a certain power margin, and its rated peak voltage and rated current (on-state average current) should be 1.5 to 2 times higher than the maximum operating voltage and maximum operating current of the controlled circuit.
The parameters such as forward voltage drop, gate trigger current, and trigger voltage of the thyristor should meet the requirements of the application circuit (referring to the gate control circuit), and should not be too high or too low, otherwise, it will affect the normal operation of the thyristor.