Ratings versus physics: are a diode’s “breakdown voltage” (physical onset of reverse conduction) and its “peak inverse voltage” (PIV, allowable reverse voltage rating) the same thing?

Introduction / Context:
Data sheets specify a maximum reverse voltage rating (often called PIV or VRRM) to keep real devices away from destructive breakdown. The physical breakdown voltage is the actual reverse voltage at which the junction undergoes avalanche or Zener breakdown.

Given Data / Assumptions:

• PIV is a rating applied for safe operation with margin.
• Breakdown voltage is a physical characteristic that may vary with temperature and current.
• We consider standard silicon rectifiers and signal diodes.

Concept / Approach:
PIV (or VRRM) is the maximum reverse voltage the diode is guaranteed to withstand repetitively without entering breakdown. The breakdown voltage is the threshold where significant reverse current begins due to avalanche/Zener effects. Designers choose PIV ratings greater than any expected reverse voltage so that operation stays below the breakdown point with margin. Thus, they are related but not “the same.”

Step-by-Step Solution:

Verification / Alternative check:
Compare data sheets: breakdown or Zener test conditions differ from VRRM; the rating is conservative to ensure reliability over tolerance and temperature.

Why Other Options Are Wrong:
Correct: misstates the relationship.

Only in vacuum or only for Zeners: nomenclature differences aside, the rating-versus-physics distinction still applies.

Common Pitfalls:
Using a diode at or above breakdown unintentionally; assuming PIV is the same as the measured breakdown on a benchtop sample without margin.

Final Answer:
Incorrect