1. When the thyristor is subjected to the reverse anode voltage, no matter what voltage the gate is subjected to, the thyristor is in the off state.
2. When the thyristor is subjected to a forward anode voltage, the thyristor is turned on only when the gate is subjected to a forward voltage.
3. When the thyristor is turned on, as long as there is a certain forward anode voltage, no matter what the gate voltage is, the thyristor remains on, that is, after the thyristor is turned on, the gate loses its function.
4. When the thyristor is turned on, when the main circuit voltage (or current) decreases to close to zero, the thyristor is turned off.