Technician exam question T7D11
Subelement T7, PRACTICAL CIRCUITS· Group T7D
Which of the following precautions should be taken when measuring in-circuit resistance with an ohmmeter?
- A.Ensure that the applied voltages are correct
- B.Ensure that the circuit is not powered (correct answer)
- C.Ensure that the circuit is grounded
- D.Ensure that the circuit is operating at the correct frequency
WhyWhen measuring in-circuit resistance with an ohmmeter, you should ensure the circuit is not powered. An ohmmeter applies its own small internal voltage to make a resistance measurement, so any external voltage already present in a powered circuit would interfere with that measurement and can damage the meter, making it essential to de-energize the circuit first, answer B. Confirming applied voltages are correct (A) doesn't apply once the circuit is unpowered, grounding (C) isn't a precaution specific to resistance measurement, and operating frequency (D) is irrelevant to a DC resistance check.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2026-2030 NCVEC Element 2 pool (public domain); the explanation above is original writing, see our methodology.
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