Advanced Qualification · A-002 Advanced components and circuits · A-002-011-011
Crystals are not applicable to which of the following?
- A Microphones
- B Lattice filters
- C Oscillators
- D Active filters
Correct answer: D — Active filters. From the official ISED question bank, verified word for word.
Why
Active filters use electronic parts like transistors and resistors to shape signals, relying on power to work, so they do not need the physical vibration of a crystal to function. The full explanation — and one for every question — is in Pro.
Practise this section
Advanced components and circuits: semiconductors, amplifier classes, oscillators, mixers, filters and digital logic.