Coast Guard Exams
Question 165Electricity/Electronics - QMED70% to pass

Which of the meters listed should only be used after a circuit has been electrically de-energized?

AI Explanation
You are correct, the answer is D) Ohmmeter. An ohmmeter should only be used on a de-energized circuit, as it measures the resistance in a circuit. Using an ohmmeter on an energized circuit can damage the meter and potentially create a safety hazard. Ammeters, wattmeters, and frequency meters can all be used to measure properties of an energized electrical circuit. The other answer choices are incorrect because ammeters, wattmeters, and frequency meters are designed to measure current, power, and frequency, respectively, on active, energized circuits. Using these meters does not require the circuit to be de-energized.