#Thyristor turn on method
triggering
gate triggering
temperature triggering
light triggering
Forward-voltage triggering occurs when the anode-cathode forward voltage is increased with the gate circuit opened. This is known as avalanche breakdown, during which junction 12 will break down. At sufficient voltages, the thyristor changes to its on state with low voltage drop and large forward current. In this case, II and 13 are already forward-biased.
In order for gate triggering to occur, the thyristor should be in the forward blocking state where the applied voltage is less than the breakdown voltage, otherwise forward-voltage triggering may occur. A single small positive voltage pulse can then be applied between the gate and the cathode. This supplies a single gate current pulse that turns the thyristor onto its on state. In practice, this is the most common method used to trigger a thyristor.
Temperature triggering occurs when the width of depletion region decreases as the temperature is increased. When the SCR is near VPO a very small increase in temperature causes junction 12 to be removed which triggers the device.
#Aictech
10 фев 2022
