General exam question G4B05
Subelement G4, AMATEUR RADIO PRACTICES· Group G4B
Why do voltmeters have high input impedance?
- A.It improves the frequency response
- B.It allows for higher voltages to be safely measured
- C.It improves the resolution of the readings
- D.It decreases the loading on circuits being measured (correct answer)
WhyVoltmeters have high input impedance to decrease the loading they place on circuits being measured. A voltmeter with high input impedance draws only a tiny current from the circuit it's probing, so it disturbs, or loads, the circuit under test as little as possible and reads closer to the true undisturbed voltage, answer D. High input impedance doesn't improve frequency response, doesn't by itself let the meter handle higher voltages, and doesn't improve display resolution, those depend on other parts of the meter's design.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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