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Zorluk: OrtaMultimeter: Resistance and Continuity

A technician is using a digital multimeter set to the resistance (ΩΩ) function to test a de-energized DC solenoid valve coil with a nominal rating of 24 Ω24\ \Omega. Which multimeter display reading indicates that the solenoid coil has an internal open circuit?

  1. A
    0.0 Ω0.0\ \Omega
  2. B
    24 Ω24\ \Omega
  3. OL\text{OL} (over-limit) or infinite resistanceCevap
  4. D
    24 kΩ24\ \text{k}\Omega

Cevap

An over-limit (OL) or infinite resistance reading on the digital multimeter display indicates an open circuit.
An open circuit occurs when there is a physical break in the conductive path of the coil winding. Because electric current cannot bridge the gap, the electrical resistance across the terminals becomes infinite (∞\infty). On a digital multimeter, infinite resistance that exceeds the instrument's measurement capability is displayed as 'OL' (over-limit).

Adım Adım Çözüm

1
Identify the electrical state being tested on the de-energized coil.
An internal open circuit means the continuous wire winding has broken, creating an incomplete path.
When a conductor or winding breaks, current can no longer pass through the component.
2
Determine the theoretical resistance value of an open circuit.
An open circuit provides infinite resistance (∞ Ω\infty\ \Omega) to the multimeter's internal test current.
Air or physical gaps between broken wire ends have extremely high dielectric resistance.
3
Correlate infinite resistance with standard digital multimeter display conventions.
Digital multimeters display infinite resistance exceeding the measurement range as 'OL' (over-limit) or '∞\infty'.
Multimeters use 'OL' to indicate that the measured resistance exceeds the measurable range of the selected scale.

Anahtar Kavram

Interpreting digital multimeter resistance displays for open circuits versus normal continuity
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Konular

Multimeter: Resistance and Continuity

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