Extra exam question E4E04
Subelement E4, AMATEUR PRACTICES· Group E4E
How can conducted noise from an automobile battery charging system be suppressed?
- A.By installing filter capacitors in series with the alternator leads
- B.By installing a noise suppression resistor and a blocking capacitor at the battery
- C.By installing a high-pass filter in series with the radio’s power lead and a low-pass filter in parallel with the antenna feed line
- D.By installing ferrite chokes on the charging system leads (correct answer)
WhyConducted noise from an automobile's battery charging system can be suppressed by installing ferrite chokes on the charging system's leads. Conducted noise from an automobile's charging system can be suppressed by installing ferrite chokes directly on the charging system's leads, which impede the high-frequency noise current from traveling along those wires without disrupting the DC charging current itself, answer D. Filter capacitors in series (rather than in parallel) with the alternator leads wouldn't function correctly, a noise suppression resistor and blocking capacitor at the battery isn't the standard fix for this specific noise source, and the high-pass/low-pass filter combination described doesn't match how this kind of conducted noise is actually suppressed.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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