Which of the following methods of turning on of a thyristor may lead to the destruction of the thyristor?

Turn ON methods of the thyristor

A thyristor can be turned on using various methods, but excessive dv/dt triggering (rate of change of voltage) can lead to undesired turn-on and potential destruction of the device.

dv/dt triggering:

• If the voltage across the thyristor changes too rapidly (high dv/dt), it can cause capacitive charging of the junctions, leading to unintended turn-on.
• This results in high surge currents, overheating, and possible permanent damage to the thyristor.
• To prevent this, a snubber circuit (RC network) is used to control dv/dt.

Light triggering:

• Used in Light-Activated Silicon-Controlled Rectifiers (LASCRs) and is generally safe.

Forward voltage triggering:

• Requires a very high forward voltage, which is not a common method in practical applications.

Gate triggering:

• The most reliable and controlled method, where a gate pulse is applied to turn on the thyristor in a controlled manner.