Basic Qualification · B-003 Station assembly, practice and safety · B-003-019-005
You need to work on a power supply that has been taken offline. What is the first thing you should do once the cabinet is open?
- A Discharge the filter capacitors
- B Bond the chassis to ground
- C Place the unit on an insulating mat
- D Short the AC input leads together
Correct answer: A — Discharge the filter capacitors. From the official ISED question bank, verified word for word.
Why
Filter capacitors store dangerous electrical energy even after the power is turned off, acting like hidden batteries that can shock you instantly. The full explanation — and one for every question — is in Pro.
Practise this section
Building a station safely: power supplies, grounding, RF exposure, lightning, feedline routing, and what a transmitter, receiver and transceiver actually do.