Testing a Fuse with a Volt-Ohm Meter (VOM) When checking whether a fuse is good or open with a handheld meter, which measurement function should you select?

Difficulty: Easy

Correct Answer: Ohms

Explanation:


Introduction / Context:
A fuse is a protective device that should present near-zero resistance when intact and an open circuit when blown. The simplest bench test confirms continuity without applying power to the circuit under test.


Given Data / Assumptions:

  • Meter has selectable functions: AC volts, DC volts, current, and resistance (ohms)/continuity.
  • Fuse is removed from the circuit to avoid parallel paths.
  • We only need to know if the fuse conducts.


Concept / Approach:

The resistance (ohms) or continuity function sources a small current and measures resulting voltage to determine resistance. A good fuse reads near 0 Ω or triggers a continuity beep; an open fuse reads OL or infinite resistance. Voltage or current modes are neither required nor safe for simple continuity checks.


Step-by-Step Solution:

Set the meter to ohms (or continuity mode).Touch probes together to verify near-zero reading/beep.Place probes on the fuse terminals; confirm near-zero reading for a good fuse.If the reading is OL/infinite, the fuse is blown.


Verification / Alternative check:

Install a known-good fuse and observe circuit operation to double-check the diagnosis.


Why Other Options Are Wrong:

Voltage ranges do not measure continuity, and current mode risks shorting the meter across a source. “None of the above” is incorrect because ohms is the standard choice.


Common Pitfalls:

Testing in-circuit (parallel paths), failing to isolate power, or using the current range by mistake can damage the meter or circuit.


Final Answer:

Ohms

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