Forward and reverse recovery times of diode

The forward recovery time of a diode is defined as the time difference between the 10 % point of diode final voltage and the time when the diode voltage reaches 90 % and remains within 10 % of final value.

The terms storage and transition times are used when diode is suddenly switched from forward bias to reverse bias.

Storage time is defined as the time interval between application of reverse bias and the time at which stored minority charge becomes zero.

Transition time is defined as the time the diode transition capacitance takes to charge from zero (This happens when stored minority charge becomes zero) to applied reverse bias.

The total time elapsed between the application of reverse bias till the diode charge fully to applied reverse bias is called as reverse recovery time. It is the sum of storage time and transition time.