Basic Qualification · B-008 Interference and suppression · B-008-002-008
What device can be used to minimize the effect of RF pickup by audio wires connected to stereo speakers, intercom amplifiers, telephones, etc.?
- ACoil on ferrite core
- BHigh-pass filter
- CAttenuator
- DSurge suppressor
Correct answer: A — Coil on ferrite core. From the official ISED question bank, verified word for word.
Why
A coil on ferrite core works by wrapping the audio wire around a special iron-like bead that acts as a trap for unwanted radio frequency energy, stopping it from turning into noise in your speakers or phones. The full explanation — and one for every question — is in Pro.
Practise this section
Interference and suppression is section B-008 of the Basic exam: When things interfere: harmonics, overload, RFI to and from your station, filters, ferrites and how to fix the neighbour's TV.
Drill B-008 — free, no account