Advanced Qualification · A-003 Measurements · A-003-004-006
The clock in a frequency counter normally uses a:
- A mechanical tuning fork
- B free-running multivibrator
- C crystal oscillator
- D self-oscillating Hartley oscillator
Correct answer: C — crystal oscillator. From the official ISED question bank, verified word for word.
Why
A frequency counter needs a timing source that stays extremely steady to count radio waves accurately, and a crystal oscillator uses a tiny piece of quartz that vibrates at a precise, unchanging rate when electricity hits it. The full explanation — and one for every question — is in Pro.
Practise this section
Measurements: meters, oscilloscopes, counters, signal generators, and what a reading actually tells you.