Bipolar Junction Transistors (Bjt) MCQs
Practice and Learn through MCQs and Quizzes. W3Definitions.com have 35 Bipolar Junction Transistors (Bjt) MCQs
A collector characteristic curve is a graph showing:
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A. emitter current (IE) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
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B. collector current (IC) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
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C. collector current (IC) versus collector-emitter voltage (VC) with (VBB) base bias voltage held constant
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D. collector current (IC) versus collector-emitter voltage (VCC) with (VBB) base bias voltage held constant
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Correct Answer: Option B
A current ratio of IC/IE is usually less than one and is called:
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A. beta
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B. theta
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C. alpha
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D. omega
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Correct Answer: Option C
A transistor may be used as a switching device or as a:
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A. fixed resistor
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B. tuning device
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C. rectifier
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D. variable resistor
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Correct Answer: Option D
An emitter-follower has a voltage gain that is __________.
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A. much less than one
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B. approximately equal to one
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C. greater than one
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D. zero
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Correct Answer: Option B
Base bias provides _________.
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A. a very stable Q point
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B. a very unstable Q point
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C. no current gain
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D. zero current in the base and collector circuits
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Correct Answer: Option B
For a C-C configuration to operate properly, the collector-base junction should be reverse biased, while forward bias should be applied to which junction?
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A. collector-emitter
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B. base-emitter
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C. collector-base
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D. cathode-anode
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Correct Answer: Option A
If a 2 mV signal produces a 2 V output, what is the voltage gain?
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A. 0.001
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B. 0.004
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C. 100
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D. 1000
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Correct Answer: Option D
If a transistor operates at the middle of the dc load line, a decrease in the current gain will move the Q point:
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A. off the load line
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B. nowhere
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C. up
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D. down
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Correct Answer: Option D
If an input signal ranges from 20–40 A (microamps), with an output signal ranging from .5–1.5 mA (milliamps), what is the ac beta?
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A. 0.05
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B. 20
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C. 50
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D. 500
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Correct Answer: Option C
If VCC = +18 V, voltage-divider resistor R1 is 4.7 k, and R2 is 1500, what is the base bias voltage?
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A. 8.70 V
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B. 4.35 V
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C. 2.90 V
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D. 0.7 V
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Correct Answer: Option B
In a C-E configuration, an emitter resistor is used for:
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A. stabilization
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B. ac signal bypass
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C. collector bias
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D. higher gain
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Correct Answer: Option A
In a transistor, collector current is controlled by:
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A. collector voltage
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B. base current
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C. collector resistance
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D. all of the above
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Correct Answer: Option B
Most of the electrons in the base of an NPN transistor flow:
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A. out of the base lead
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B. into the collector
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C. into the emitter
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D. into the base supply
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Correct Answer: Option B
Often a common-collector will be the last stage before the load; the main function(s) of this stage is to:
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A. provide voltage gain
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B. provide phase inversion
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C. provide a high-frequency path to improve the frequency response
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D. buffer the voltage amplifiers from the low-resistance load and provide impedance matching for maximum power transfer
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Correct Answer: Option D
The C-B configuration is used to provide which type of gain?
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A. voltage
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B. current
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C. resistance
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D. power
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Correct Answer: Option A
The ends of a load line drawn on a family of curves determine:
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A. saturation and cutoff
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B. the operating point
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C. the power curve
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D. the amplification factor
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Correct Answer: Option A
The input resistance of the base of an emitter-follower is usually _________.
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A. very low
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B. very high
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C. shorted to ground
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D. open
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Correct Answer: Option B
The input/output relationship of the common-collector and common-base amplifiers is:
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A. 270 degrees
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B. 180 degrees
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C. 90 degrees
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D. 0 degrees
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Correct Answer: Option D
The phase difference between the input and output ac voltage signals of a common-emitter amplifier is __________.
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A. 0º
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B. 90º
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C. 180º
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D. 360º
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Correct Answer: Option C
The Q point on a load line may be used to determine:
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A. VC
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B. VCC
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C. VB
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D. IC
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Correct Answer: Option C
Three different Q points are shown on a dc load line. The upper Q point represents the:
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A. minimum current gain
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B. intermediate current gain
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C. maximum current gain
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D. cutoff point
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Correct Answer: Option C
To operate properly, a transistor’s base-emitter junction must be forward biased with reverse bias applied to which junction?
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A. collector-emitter
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B. base-collector
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C. base-emitter
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D. collector-base
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Correct Answer: Option D
Total emitter current is:
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A. IE – IC
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B. IC + IE
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C. IB + IC
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D. IB – IC
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Correct Answer: Option C
VCE approximately equals ________ when a transistor switch is cut off.
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A. VCC
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B. VB
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C. 0.2 V
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D. 0.7 V
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Correct Answer: Option A
VCE approximately equals ________ when a transistor switch is in saturation.
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A. VC
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B. VB
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C. 0.3 V
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D. 0.7 V
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Correct Answer: Option C
Voltage-divider bias provides:
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A. an unstable Q point
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B. a stable Q point
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C. a Q point that easily varies with changes in the transistor's current gain
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D. a Q point that is stable and easily varies with changes in the transistors current gain
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Correct Answer: Option B
What is the collector current for a C-E configuration with a beta of 100 and a base current of 30 A?
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A. 30 A
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B. .3 A
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C. 3 mA
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D. 3 MA
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Correct Answer: Option C
What is the current gain for a common-base configuration where IE = 4.2 mA and IC = 4.0 mA?
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A. 16.80
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B. 1.05
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C. 0.20
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D. 0.95
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Correct Answer: Option D
When a silicon diode is forward biased, what is VBE for a C-E configuration?
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A. voltage-divider bias
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B. 0.4 V
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C. 0.7 V
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D. emitter voltage
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Correct Answer: Option C
When transistors are used in digital circuits they usually operate in the:
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A. active region
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B. breakdown region
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C. saturation and cutoff regions
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D. linear region
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Correct Answer: Option C
Which is beta’s current ratio?
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A. IC/IB
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B. IC/IE
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C. IB/IE
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D. IE/IB
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Correct Answer: Option A
Which is the higher gain provided by a C-E configuration?
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A. voltage
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B. current
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C. resistance
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D. power
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Correct Answer: Option D
With a PNP circuit, the most positive voltage is probably:
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A. ground
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B. VC
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C. VBE
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D. VCC
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Correct Answer: Option A
With low-power transistor packages, the base terminal is usually the:
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A. tab end
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B. middle
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C. right end
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D. stud mount
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Correct Answer: Option B
With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be:
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A. open
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B. infinite
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C. low resistance
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D. high resistance
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Correct Answer: Option C