Reverse recovery time definition for a power diode In a power diode, reverse recovery time trr is measured from the instant forward current crosses zero to the instant the reverse recovery current decays to what fraction of its peak value?

Introduction / Context:
Reverse recovery affects switching losses, EMI, and commutation failure risk in converters. A precise definition of trr is necessary to interpret datasheets.

Given Data / Assumptions:

• Standard diode reverse recovery definition per common practice.
• Focus on the current threshold used to terminate trr measurement.

Concept / Approach:
After forward conduction, stored charge causes a transient reverse current when the diode is reverse-biased. The reverse recovery time is defined from forward current zero crossing to the time when reverse current falls to 10% of its peak reverse value (unless otherwise specified).

Step-by-Step Solution:
Identify start: i_D transitions through zero into reverse.Identify peak reverse current I_RRM.Measure time until i_D decays to 0.1 * I_RRM → trr.

Verification / Alternative check:
Many datasheets annotate trr using a standard test circuit and specify 10% as the end criterion for the reverse tail.

Why Other Options Are Wrong:
50% / 25%: Too early; would understate trr.
0%: Unrealistic; the tail asymptotically approaches zero and measurement would be ambiguous.

Common Pitfalls:
Confusing trr with tq (thyristor turn-off time) or using nonstandard thresholds; always confirm the datasheet’s stated criterion.

Final Answer:
10% of peak reverse current