Topic Outline
- MCQs in Unbiased Transistor
- MCQs in Biased Transistor
- MCQs in Transistor Currents
- MCQs in CE Connection
- MCQs in Base Curve and Collector Curves
- MCQs in Transistor Approximation
- MCQs in Surface-Mount Transistors
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1. A transistor has how many doped regions?
- a. 1
- b. 2
- c. 3
- d. 4
2. What is one important thing transistors do?
- a. Amplify weak signals
- b. Rectify line voltage
- C. Regulate voltage
- d. Emit light
3. Who invented the first junction transistor?
- a. Bell
- b. Faraday
- c. Marconi
- d. Schockley
4. In an npn transistor, the majority carriers in the base are
- a. Free electrons
- b. Holes
- c. Neither
- d. Both
5. The barrier potential across each silicon depletion layer is
- a. 0
- b. 0.3 V
- c. 0.7 V
- d. 1 V
6. The emitter diode is usually
- a. Forward-biased
- b. Reverse-biased
- c. Nonconducting
- d. Operating in the breakdown region
7. For normal operation of the transistor, the collector diode has to be
- a. Forward-biased
- b. Reverse-biased
- c. Nonconducting
- d. Operating in the breakdown region
8. The base of an npn transistor is thin and
- a. Heavily doped
- b. Lightly doped
- c. Metallic
- d. Doped by a pentavalent material
9. Most of the electrons in the base of an npn transistor flow
- a. Out of the base lead
- b. Into the collector
- c. Into the emitter
- d. Into the base supply
10. Most of the electrons in the base of an npn transistor do not recombine because they
- a. Have a long lifetime
- b. Have a negative charge
- c. Must flow a long way through the base
- d. Flow out of the base
11. Most of the electrons that flow through the base will
- a. Flow into the collector
- b. Flow out of the base lead
- c. Recombine with base holes
- d. Recombine with collector holes
12. The current gain of a transistor is the ratio of the
- a. Collector current to emitter current
- b. Collector current to base current
- c. Base current to collector current
- d. Emitter current to collector current
13. Increasing the collector supply voltage will increase
- a. Base current
- b. Collector current
- c. Emitter current
- d. None of the above
14. The fact that only a few holes are in the base region means the base is
- a. Lightly doped
- b. Heavily doped
- c. Undoped
- d. None of the above
15. In a normally biased npn transistor, the electrons in the emitter have enough energy to overcome the barrier potential of the
- a. Base-emitter junction
- b. Base-collector junction
- c. Collector-base junction
- d. Recombination path
16. When a free electron recombines with a hole in the base region, the free electron becomes
- a. Another free electron
- b. A valence electron
- c. A conduction-band electron
- d. A majority carrier
17. What is the most important fact about the collector current?
- a. It is measured in milliamperes.
- b. It equals the base current divided by the current gain.
- c. It is small.
- d. It approximately equals the emitter current.
18. If the current gain is 200 and the collector current is 100 mA, the base current is
- a. 0.5 mA
- b. 2 mA
- c. 2 A
- d. 20 A
19. The base-emitter voltage is usually
- a. Less than the base supply voltage
- b. Equal to the base supply voltage
- c. More than the base supply voltage
- d. Cannot answer
20. The collector-emitter voltage is usually
- a. Less than the collector supply voltage
- b. Equal to the collector supply voltage
- c. More than the collector supply voltage
- d. Cannot answer
21. The power dissipated by a transistor approximately equals the collector current times
- a. Base-emitter voltage
- b. Collector-emitter voltage
- c. Base supply voltage
- d. 0.7 V
22. A small collector current with zero base current is caused by the leakage current of the
- a. Emitter diode
- b. Collector diode
- c. Base diode
- d. Transistor
23. A transistor acts like a diode and a
- a. Voltage source
- b. Current source
- c. Resistance
- d. Power supply
24. If the base current is 100 mA and the current gain is 30, the collector current is
- a. 300 mA
- b. 3 A
- c. 3.33 A
- d. 10 A
25. The base-emitter voltage of an ideal transistor is
- a. 0
- b. 0.3 V
- c. 0.7 V
- d. 1 V
26. If you recalculate the collector-emitter voltage with the second approximation, the answer will usually be
- a. Smaller than the ideal value
- b.. The same as the ideal value
- c. Larger than the ideal value
- d. Inaccurate
27. In the active region, the collector current is not changed significantly by
- a. Base supply voltage
- b. Base current
- c. Current gain
- d. Collector resistance
28. The base-emitter voltage of the second approximation is
- a. 0
- b. 0.3 V
- c. 0.7 V
- d. 1 V
29. If the base resistor is open, what is the collector current?
- a. 0
- b. 1 mA
- c. 2 mA
- d. 10 mA
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