Rectifier reliability: “A common failure observed in rectifier circuits is an open diode.” Evaluate this statement for typical power supplies and small-signal rectifiers.

Introduction / Context:
When rectifiers fail, technicians often diagnose “open” or “shorted” diodes. Understanding which faults are commonly encountered helps in troubleshooting power supplies and detector circuits.

Given Data / Assumptions:

• Silicon rectifier diodes operating within typical ratings.
• Thermal and surge stresses can occur (inrush, transients).
• Field observations include both open-circuit and short-circuit failures.

Concept / Approach:
Diodes can fail open due to bond-wire burnout or junction damage from surge currents, leaving no conduction path. They can also fail short when the junction is punctured (catastrophic breakdown). In low-power and many field cases, “open diode” symptoms—no output DC, large ripple, or one half-cycle missing—are commonly observed and easy to diagnose with a meter.

Step-by-Step Solution:

Verification / Alternative check:
Service manuals often list diode checks (forward/reverse resistance or diode-test mode) precisely because open or short faults occur frequently and are straightforward to verify.

Why Other Options Are Wrong:
Incorrect: contradicts broad troubleshooting experience.

Only with Schottky or only at high temperature: while temperature and technology affect failure modes, open faults are not restricted to a specific diode type or solely to thermal extremes.

Common Pitfalls:
Assuming all diode failures are shorts; failing to check both forward and reverse readings; overlooking intermittent opens caused by cracked leads or cold solder joints.

Final Answer:
Correct