Measuring a good 2 A fuse with a digital multimeter set to resistance (Ω), range 20k: what reading should you expect?
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A0.00
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B0.02
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C0.20
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D2.00
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ENone of the above
Answer
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