Basic Qualification · B-004 Circuit components · B-004-005-009
What term describes a vacuum tube with a cathode, a single grid and a plate?
- A Diode
- B Tetrode
- C Pentode
- D Triode
Correct answer: D — Triode. From the official ISED question bank, verified word for word.
Why
A vacuum tube with a cathode, one grid, and a plate is called a Triode because the prefix "tri" means three, matching the three active elements inside the tube. The full explanation — and one for every question — is in Pro.
Practise this section
The parts inside the box: resistors, capacitors, inductors, diodes, transistors, tubes and what each does in a circuit.