In a thyristor _________ is the time required for the forward blocking voltage to fall from 10% of an anode voltage to the on-state voltage drop of the device.

Switching Characteristics of SCR

SCR or Thyristor Turn-on Time: 

Thyristor turn-on time may be defined as the time required by the SCR to change its state from forward blocking mode to forward conduction mode when a gate pulse is applied.

The total turn-on time of SCR comprises three different time intervals:

Delay Time:

• It is the time between the instant at which the gate current reaches 90% of its final value and the instant at which the anode current reaches 10% of its final value.

Rise Time:

• Rise time is the time taken by the anode current to rise from 10% of its final value to 90% of its final value. 

Spread Time:

• It is the time taken by the anode current to rise from 90% of its final value to 100%. 
• It is the time required for the forward blocking voltage to fall from 10% of an anode voltage to the on-state voltage drop of the device.