Measuring a good 2 A fuse with a digital multimeter set to resistance (Ω), range 20k: what reading should you expect?

Difficulty: Easy

Correct Answer: 0.00

Explanation:


Introduction / Context:
A quick continuity test confirms whether a fuse is intact. When using a DMM on an ohms range, a good fuse should present very low resistance. Understanding expected readings prevents misdiagnosis due to range selection or probe contact issues.


Given Data / Assumptions:

  • DMM selector is on DC/Ω, resistance range 20k (20,000 Ω full scale).
  • Fuse rating 2 A, typical cold resistance near 0 Ω.
  • Probes and contact points clean and firmly connected.


Concept / Approach:
Continuity of a fuse is essentially a near-short. On a high-ohms range, a near-zero resistance will display ~0.00 on many meters. Any significant nonzero resistance suggests a bad probe contact or a partially damaged fuse (rare). An open fuse reads over-range (often shown as OL).


Step-by-Step Solution:

Zero-check the meter by touching probe tips together; reading should approach 0.00.Place probes across the fuse terminals.Interpret display: ~0.00 indicates a good fuse; OL indicates open fuse.If uncertain, repeat on a lower ohms range for more resolution.


Verification / Alternative check:
Use the continuity beeper mode; a solid tone confirms near-zero resistance. Visual inspection of the fuse element can corroborate.


Why Other Options Are Wrong:

  • 0.02 / 0.20 / 2.00: Suggests significant resistance; atypical for a good fuse and likely due to contact resistance or wrong interpretation.
  • None of the above: Incorrect because ~0.00 is expected.


Common Pitfalls:
Measuring in-circuit (parallel paths skew results), dirty probe tips, and using continuity on fuses with surface oxidation causing intermittent readings.


Final Answer:
0.00

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