When testing a diode with an ohmmeter (forward and reverse measurements), what does a low resistance reading in both directions indicate about the diode's condition?

Introduction / Context:
A healthy diode conducts in the forward direction (low resistance) and blocks in the reverse direction (high resistance). Ohmmeter checks are quick diagnostics for shorts or opens. This question asks you to interpret the specific case where both directions appear low in resistance.

Given Data / Assumptions:

• Digital multimeter used in resistance or diode-test mode.
• Forward measurement: low resistance (or ~0.5–0.8 V drop for silicon).
• Reverse measurement: should be very high resistance (open-like).

Concept / Approach:
If the reverse measurement also shows low resistance, the PN junction is no longer blocking. This usually indicates a shorted diode (junction failure), which is a fault condition. Conversely, a high resistance in both directions indicates an open diode.

Step-by-Step Interpretation:
Measure forward: expect low R or typical V_f.Measure reverse: expect very high R (no conduction).Observation: low R both ways → diode conducts regardless of polarity → failed (shorted).

Verification / Alternative check:
Using diode-test mode, a shorted diode shows near 0 V in both forward and reverse polarity; an open diode shows “OL” (over-limit) both ways. A good diode shows ~0.2–0.3 V (Schottky) or ~0.6–0.7 V (silicon) forward, and “OL” reverse.

Why Other Options Are Wrong:

• Open: Would read high resistance both ways.
• Satisfactory / not the problem: A good diode must block in reverse, not conduct.

Common Pitfalls:

• Measuring in-circuit; parallel paths can mislead readings. Lift a lead to confirm.
• Confusing resistance mode with diode-test mode readings.

Final Answer:
faulty