Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-002-008
In a grounded grid amplifier using a triode vacuum tube, what would be the approximate B+ voltage required for an output of 400 watts at 400 mA with approximately 50 percent efficiency?
- A3000 volts
- B1000 volts
- C2000 volts
- D500 volts
Correct answer: C — 2000 volts. From the official ISED question bank, verified word for word.
Why
To get 400 watts out with 50 percent efficiency, the amplifier must draw 800 watts of power from the power supply. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing is section A-005 of the Advanced exam: Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.
Drill A-005 — free, no account