Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-002-007
In a grounded grid amplifier using a triode vacuum tube, the secondary winding of a transformer is connected directly to the vacuum tube. This transformer provides:
- A B+ (high voltage)
- B Screen voltage
- C filament voltage
- D B- (bias)
Correct answer: C — filament voltage. From the official ISED question bank, verified word for word.
Why
In a triode vacuum tube, the filament (or heater) must be warmed up to release electrons, and this heating requires a specific low-voltage supply. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.