Gibilisco: MCQ in Electron Tubes | ECE Board Exam

(Last Updated On: March 16, 2020)

Multiple choice questions in Electron Tubes

This is the Multiple Choice Questions (MCQs) in Chapter 29: Electron Tubes from the book Teach Yourself Electricity and Electronics, 5th edition by Stan Gibilisco. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Start Practice Exam Test Questions

1. One difference between a triode and an N-channel FET is that:

  • A. Triodes work with lower voltages.
  • B. Triodes are more compact.
  • C. Triodes need more voltage.
  • D. Triodes don’t need filaments.

2. The control grid of a tube corresponds to the:

  • A. Source of an FET.
  • B. Collector of a bipolar transistor.
  • C. Anode of a diode.
  • D. Gate of an FET.

3. The intensity of the electron flow in a vacuum tube depends on all of the following except:

  • A. The gate voltage.
  • B. The power supply voltage.
  • C. The grid voltage.
  • D. The voltage between the cathode and the plate.

4. Which type of tube maintains constant voltage drop with changes in current?

  • A. A triode.
  • B. A gas-filled regulator.
  • C. A tetrode.
  • D. A pentagrid converter.

5. In a tube with a directly heated cathode:

  • A. The filament is separate from the cathode.
  • B. The grid is connected to the filament.
  • C. The filament serves as the cathode.
  • D. There is no filament.

6. In a tube with a cold cathode:

  • A. The filament is separate from the cathode.
  • B. The grid is connected to the filament.
  • C. The filament serves as the cathode.
  • D. There is no filament.

7. A screen grid enhances tube operation by:

  • A. Decreasing the gain.
  • B. Decreasing the plate voltage.
  • C. Decreasing the grid-to-plate capacitance.
  • D. Pulling excess electrons from the plate.

8. A tube with three grids is called a:

  • A. Triode.
  • B. Tetrode.
  • C. Pentode.
  • D. Hexode.

9. A tube type radio receiver:

  • A. Is bulky and heavy.
  • B. Requires low voltage.
  • C. Is more sensitive than a transistorized radio.
  • D. All of the above.

10. An advantage of a grounded-grid power amplifier is:

  • A. Excellent sensitivity.
  • B. High impedance.
  • C. Low noise.
  • D. Good stability.

11. A heptode tube has:

  • A. Two grids.
  • B. Three grids.
  • C. Five grids.
  • D. Seven grids.

12. The electron gun in a CRT is another name for its:

  • A. Cathode.
  • B. Anode.
  • C. Control grid.
  • D. Screen grid.

13. The electron beam in an electrostatic CRT is bent by:

  • A. A magnetic field.
  • B. An electric field.
  • C. A fluctuating current.
  • D. A constant current.

14. The horizontal displacement on an oscilloscope CRT screen is usually measured in:

  • A. Frequency per unit division.
  • B. Current per unit division.
  • C. Time per unit division.
  • D. Voltage per unit division.

15. In a time-domain oscilloscope, the waveform to be analyzed is usually applied to the:

  • A. Control grid plates or coils.
  • B. Anode plates or coils.
  • C. Vertical deflection plates or coils.
  • D. Horizontal deflection plates or coils.

16. A vidicon camera tube is noted for its:

  • A. Sensitivity.
  • B. Large size.
  • C. Heavy weight.
  • D. Rapid response.

17. In a magnetron, as the frequency is increased:

  • A. The achievable power output increases.
  • B. The achievable power output decreases.
  • C. The output power stays the same.
  • D. The output power increases and decreases alternately.

18. The paths of the electrons in a magnetron are spirals, rather than straight lines, because of:

  • A. The extreme voltage used.
  • B. The longitudinal magnetic flux.
  • C. The bunching-up of the electrons.
  • D. The shapes of the cavities.

19. A klystron is noted for its:

  • A. Spiralling electrons.
  • B. Low noise output.
  • C. High achievable output power.
  • D. Magnetic-field intensity.

20. In a multicavity klystron, the electrons:

  • A. Have variable speed.
  • B. Travel in circles.
  • C. Are reflected by the cavities.
  • D. Are drawn out via the cathode.

Complete List of Multiple Choice Questions from this Book

Check your work.

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