MCQs in Boylestad Bipolar Junction Transistors

This is the Multiple Choice Questions in Bipolar Junction Transistors from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Online Questions and Answers Topic Outline

• MCQs in Transistor Construction
• MCQs in Transistor Operation
• MCQs in Common-Base Configuration
• MCQs in Transistor Amplifying Action
• MCQs in Common-Emitter Configuration
• MCQs in Common-Collector Configuration
• MCQs in Limits of Operation
• MCQs in Transistor Specification Sheet
• MCQs in Transistor Testing
• MCQs in Transistor Casing and Terminal Identification

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. In what decade was the first transistor created?

• A)    1930s
• B)    1940s
• C)    1950s
• D)    1960s

2. How many layers of material does a transistor have?

• A)    1
• B)    2
• C)    3
• D)    4

3. What is the ratio of the total width to that of the center layer for a transistor?

• A)    1:15
• B)    1:150
• C)    15:1
• D)    150:1

4. Which of the following is (are) the terminal(s) of a transistor?

• A)    Emitter
• B)    Base
• C)    Collector
• D)    All of the above

5. List the types of bipolar junction transistors.

• A)    ppn, npn
• B)    pnp, npn
• C)    npp, ppn
• D)    nnp, pnp

6. Transistors are _____-terminal devices.

• A)    2
• B)    3
• C)    4
• D)    5

7. How many carriers participate in the injection process of a unipolar device?

• A)    1
• B)    2
• C)    0
• D)    3

8. Which component of the collector current I_C is called the leakage current?

• A)    Majority
• B)    Independent
• C)    Minority
• D)    None of the above

9. For a properly biased pnp transistor, let I_C = 10 mA and I_E = 10.2 mA. What is the level of I_B?

• A)    0.2 A
• B)    200 mA
• C)    200 µA
• D)    20.2 mA

10. Calculate minority current I_CO if I_C = 20.002 mA and I_C majority = 20 mA.

• A)    2 µA
• B)    0.002 µA
• C)    2 nA
• D)    2 pA

11. Which of the following regions is (are) part of the output characteristics of a transistor?

• A)    Active
• B)    Cutoff
• C)    Saturation
• D)    All of the above

12. In which region are both the collector-base and base-emitter junctions forward-biased?

• A)    Active
• B)    Cutoff
• C)    Saturation
• D)    All of the above

13. How much is the base-to-emitter voltage of a transistor in the "on" state?

• A)    0 V
• B)    0.7 V
• C)    0.7 mV
• D)    Undefined

14. In the active region, while the collector-base junction is _____-biased, the base-emitter is _____-biased.

• A)    forward, forward
• B)    forward, reverse
• C)    reverse, forward
• D)    reverse, reverse

15. What is β_dc equal to?

• A)    I_B / I_E
• B)    I_C / I_E
• C)    I_C / I_B
• D)    None of the above

16. What are the ranges of the ac input and output resistance for a common-base configuration?

• A)    10 Ω–100 Ω, 50 k Ω–1 MΩ
• B)    50 kΩ –1 MΩ, 10 Ω –100 Ω
• C)    10 Ω –100 kΩ, 50 Ω –1 kΩ
• D)    None of the above

17. For what kind of amplifications can the active region of the common-emitter configuration be used?

• A)    Voltage
• B)    Current
• C)    Power
• D)    All of the above

18. Use this table of collector characteristics to calculate βac at V_CE = 15 V and I_B = 30 µA.

• A)    100
• B)    106
• C)    50
• D)    400

19. Calculate βdc at V_CE = 15 V and I_B = 30 µA.

• A)    100
• B)    116
• C)    50
• D)    110

20. Which of the following configurations can a transistor set up?

• A)    Common-base
• B)    Common-emitter
• C)    Common-collector
• D)    All of the above

21. Determine the value of α when β = 100.

• A)    1.01
• B)    101
• C)    0.99
• D)    Cannot be solved with the information provided

22. What is the most frequently encountered transistor configuration?

• A)    Common-base
• B)    Common-collector
• C)    Common-emitter
• D)    Emitter-collector

23. β_dc for this set of collector characteristics is within _____ percent of β_ac.

• A)    2
• B)    5
• C)    7
• D)    10

24. β_dc = ________

• A)    I_B / I_E
• B)    I_C / I_E
• C)    I_C / I_B
• D)    None of the above

25. What is (are) the component(s) of most specification sheets provided by the manufacturer?

• A)    Maximum ratings
• B)    Thermal characteristics
• C)    Electrical characteristics
• D)    All of the above

26. What is (are) the component(s) of electrical characteristics on the specification sheets?

• A)    On
• B)    Off
• C)    Small-signal characteristics
• D)    All of the above

27. Most specification sheets are broken down into _____.

• A)    maximum ratings
• B)    thermal characteristics
• C)    electrical characteristics
• D)    All of the above

28. An example of a pnp silicon transistor is a 2N4123.

• A)    True
• B)    False

29. Which of the following equipment can check the condition of a transistor?

• A)    Current tracer
• B)    Digital display meter (DDM)
• C)    Ohmmeter (VOM)
• D)    All of the above

30. Which of the following can be obtained from the last scale factor of a curve tracer?

• A)    h_FE
• B)    α_dc
• C)    α_ac
• D)    β_ac

31. Calculate β_ac for I_C = 15 mA and V_CE = 5 V.

• A)    200
• B)    180
• C)    220
• D)    None of the above

32. What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter?

• A)    100 Ω to a few kΩ, exceeding 100 kΩ
• B)    Exceeding 100 kΩ, 100 Ω to a few kΩ
• C)    Exceeding 100 kΩ, exceeding 100 kΩ
• D)    100 Ω to a few kΩ, 100 Ω to a few kΩ

33. What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?

• A)    Faulty device
• B)    Good device
• C)    Bad ohmmeter
• D)    None of the above

34. A transistor can be checked using a(n) _____.

• A)    curve tracer
• B)    digital meter
• C)    ohmmeter
• D)    Any of the above

35. How many individual pnp silicon transistors can be housed in a 14-pin plastic dual-in-line package?

• A)    4
• B)    7
• C)    10
• D)    14

Fill-in-the-blanks Questions

1. All amplifiers should have at least _____ terminals with _____ terminal(s) controlling the flow between _____ other terminal(s).

• A)    2, 1, 1
• B)    3, 1, 2
• C)    3, 2, 1
• D)    3, 0, 3

2. The outer layers of a transistor are _____ the sandwiched layer.

• A)    much smaller than
• B)    the same as
• C)    much larger than
• D)    None of the above

3. The doping of the sandwiched layer is _____ that of the outer layers.

• A)    considerably less than
• B)    the same as
• C)    considerably more than
• D)    None of the above

4. The lower doping level _____ the conductivity and _____ the resistivity of the material.

• A)    increases, decreases
• B)    increases, increases
• C)    decreases, decreases
• D)    decreases, increases

5. The term bipolar reflects the fact that _____ and _____ participate in the injection process into the oppositely polarized material.

• A)    holes, neutrons
• B)    holes, electrons
• C)    neutrons, electrons
• D)    None of the above

6. One p-n junction of a transistor is _____-biased and the other one is _____-biased in the active region.

• A)    reverse, reverse
• B)    forward, forward
• C)    reverse, forward
• D)    None of the above

7. The magnitude of the base current is typically on the order of _____ as compared to _____ for the emitter.

• A)    µA, µA
• B)    µA, mA
• C)    mA, µA
• D)    mA, mA

8. The base current is the _____ of the emitter and collector currents.

• A)    sum
• B)    difference
• C)    product
• D)    None of the above

9. The _____ region is the region normally employed for linear (undistorted) amplifiers.

• A)    active
• B)    cutoff
• C)    saturation
• D)    All of the above

10. In the cutoff region the collector-base junction is _____-biased and the base-emitter junction is _____-biased for a transistor.

• A)    reverse, forward
• B)    forward, reverse
• C)    reverse, reverse
• D)    forward, forward

11. In the saturation region the collector-base junction is _____-biased and the base-emitter junction is _____-biased for a transistor.

• A)    reverse, forward
• B)    forward, reverse
• C)    reverse, reverse
• D)    forward, forward

12. For practical transistors the level of alpha typically extends from _____ to _____ with most approaching the higher end of the range.

• A)    0.0, 1
• B)    0.90, 0.998
• C)    50, 400
• D)    None of the above

13. Typical values of voltage amplification for the common-base configurations vary from _____ and the current gain is always _____ .

• A)    less than 1, 50 to 300
• B)    50 to 300, larger than 1
• C)    50 to 300, less than 1
• D)    larger than 1, 50 to 300

14. If a value of beta.gif is specified for a particular transistor configuration it will normally be used for _____ calculations.

• A)    ac
• B)    dc
• C)    ac and dc
• D)    None of the above

15. The common-collector configuration has a _____ input impedance and a _____ output impedance.

• A)    low, high
• B)    high, low
• C)    high, high
• D)    low, low

16. The active region of a transistor is bounded by the _____.

• A)    cutoff region
• B)    saturation region
• C)    power dissipation curve
• D)    All of the above

17. The "on" and "off" characteristics refer to _____ limits while the small-signal characteristics indicate the parameters of importance to _____ operation.

• A)    ac, dc
• B)    dc, ac
• C)    ac, dc and ac
• D)    dc and ac, dc

18. The step function (per step) of a curve tracer reveals the scale for _____.

• A)    collector current I_C
• B)    V_CE voltage
• C)    base current I_B
• D)    All of the above

19. The level of _____ is determined and displayed by advanced digital meters.

• A)    V_CE
• B)    I_B
• C)    I_C
• D)    β_dc

20. The level of _____ is determined and displayed by advanced digital meters if using diode-testing mode.

• A)    V_BE
• B)    I_C
• C)    I_B
• D)    I_E

21. When checking a transistor by ohmmeter, a relatively _____ resistance is displayed for a forward-biased junction and _____ resistance for a reverse-biased junction.

• A)    low, very high
• B)    low, low
• C)    high, high
• D)    high, very low

22. An OL indication on an advanced digital meter indicates _____ while checking a transistor.

• A)    forward bias
• B)    reverse bias
• C)    definitely a defective transistor
• D)    None of the above

23. If the positive lead of an ohmmeter is connected to the base and the negative lead to the emitter, a low resistance reading would indicate a _____ transistor and a high resistance reading would indicate a _____ transistor.

• A)    npn, pnp
• B)    pnp, npn
• C)    npn, npn
• D)    pnp, pnp

24. The leads of a transistor are typically made of _____.

• A)    gold
• B)    aluminum
• C)    nickel
• D)    All of the above

25. There is(are) _____ in the internal construction of a TO-92 package.

• A)    gold bond wires
• B)    a copper frame
• C)    epoxy encapsulation
• D)    All of the above

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credit: Robert L. Boylestad© 2014 www.PinoyBIX.org