Question 172Electricity/Electronics - 1st Asst/Chief70% to pass
While troubleshooting a circuit in an engine room central control console, a resistor is suspected of being faulty. Which of the following precautions must be observed if an analog or digital multimeter set up as an ohmmeter is to be used to check its value?
AI Explanation
The correct answer is A) The resistor's circuit must be de-energized and at least one end of the resistor isolated by disconnecting.
This is the correct answer because when troubleshooting a circuit with an ohmmeter, it is essential to ensure that the circuit is de-energized and isolated. If the circuit is still energized, measuring the resistance of a component could result in damage to the meter or the component itself. Isolating the resistor by disconnecting at least one end ensures that there is no current flow through the circuit during the resistance measurement.
The other options are incorrect because:
B) Polarity is not a concern when using an ohmmeter, as it measures resistance, not voltage.
C) Twisting the meter leads does not affect the magnetic fields in a resistance measurement.
D) Grounding the meter case is not necessary when using an ohmmeter to measure resistance.
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