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Zorluk: ZorMultimeter: Resistance and Continuity

An avionics technician is troubleshooting a de-energized, three-conductor wiring harness that is disconnected at both ends. Using a digital multimeter set to the resistance (Ω\Omega) mode, the technician records the following measurements:

- Probing between Conductor 1 and Conductor 2 at the near end yields a reading of 0.3 Ω0.3\ \Omega.
- Probing between Conductor 1 and Conductor 3 at the near end yields a reading of OL\text{OL} (overload/infinite resistance).
- After placing a temporary jumper wire between Conductor 1 and Conductor 3 at the far end, probing between Conductor 1 and Conductor 3 at the near end continues to read OL\text{OL}.

Which of the following diagnoses is conclusively supported by these test results?

  1. A
    Conductor 1 and Conductor 2 have an open circuit, while Conductor 3 maintains normal end-to-end continuity.
  2. Conductor 1 and Conductor 2 are shorted together, and Conductor 3 has an internal open circuit fault.Cevap
  3. C
    All conductors are intact, but accurate resistance and continuity readings require the harness to be connected to live operating voltage.
  4. D
    Conductor 1 and Conductor 2 demonstrate normal dielectric insulation, whereas the OL\text{OL} reading indicates zero resistance.

Cevap

Conductor 1 and Conductor 2 are shorted together, and Conductor 3 has an internal open circuit fault.
In a de-energized, disconnected harness, isolated conductors should show infinite resistance (OL\text{OL}). The 0.3 Ω0.3\ \Omega reading between Conductor 1 and Conductor 2 indicates an unintended low-resistance connection (short circuit). When a jumper is placed at the far end between Conductor 1 and Conductor 3, a closed loop should be formed with near-zero resistance; the persistent OL\text{OL} display proves the path is broken, confirming an open circuit fault in Conductor 3.

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1
Analyze the resistance measurement between disconnected Conductors 1 and 2.
A reading of 0.3 Ω0.3\ \Omega between two wires that should be electrically isolated indicates continuity where none should exist.
Independent conductors in a disconnected harness should exhibit infinite resistance (open circuit). A reading near 0 Ω0\ \Omega confirms an insulation breakdown or physical short circuit between Conductors 1 and 2.
2
Evaluate the loop continuity test between Conductors 1 and 3 with a far-end jumper installed.
The multimeter continues to read OL\text{OL} (overload / infinite resistance).
Jumpering two conductors at the far end forms a continuous loop. If both conductors and the jumper were intact, the near-end resistance should be near zero. A reading of OL\text{OL} indicates that the loop is broken, identifying an open circuit in Conductor 3 (since Conductor 1 is continuous as established in the first test).
3
Synthesize the two findings into a definitive circuit diagnosis.
Conductors 1 and 2 are shorted together, and Conductor 3 is open.
Both fault conditions are independently verified by standard multimeter resistance and continuity interpretation rules.

Anahtar Kavram

Interpreting Multimeter Resistance and Continuity Readings in Wiring Fault Diagnosis
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Konular

Multimeter: Resistance and Continuity

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