Bipolar Junction Transistors (BJT)

mcqspedia.com has 35 Question/Answers about Topic Bipolar Junction Transistors (BJT)

The input resistance of the base of an emitter-follower is usually _________.

The input resistance of the base of an emitter-follower is usually _________.
  • A. very low
  • B. very high
  • C. shorted to ground
  • D. open
  • Correct Answer: Option B

An emitter-follower has a voltage gain that is __________.

An emitter-follower has a voltage gain that is __________.
  • A. much less than one
  • B. approximately equal to one
  • C. greater than one
  • D. zero
  • Correct Answer: Option B

Base bias provides _________.

Base bias provides _________.
  • A. a very stable Q point
  • B. a very unstable Q point
  • C. no current gain
  • D. zero current in the base and collector circuits
  • Correct Answer: Option B

VCE approximately equals ________ when a transistor switch is in saturation.

VCE approximately equals ________ when a transistor switch is in saturation.
  • A. VC
  • B. VB
  • C. 0.3 V
  • D. 0.7 V
  • Correct Answer: Option C

The phase difference between the input and output ac voltage signals of a common-emitter amplifier is __________.

The phase difference between the input and output ac voltage signals of a common-emitter amplifier is __________.
  • A.
  • B. 90º
  • C. 180º
  • D. 360º
  • Correct Answer: Option C

VCE approximately equals ________ when a transistor switch is cut off.

VCE approximately equals ________ when a transistor switch is cut off.
  • A. VCC
  • B. VB
  • C. 0.2 V
  • D. 0.7 V
  • Correct Answer: Option A

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?

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?
  • A. 0.05
  • B. 20
  • C. 50
  • D. 500
  • Correct Answer: Option C

If a 2 mV signal produces a 2 V output, what is the voltage gain?

If a 2 mV signal produces a 2 V output, what is the voltage gain?
  • A. 0.001
  • B. 0.004
  • C. 100
  • D. 1000
  • Correct Answer: Option D

What is the collector current for a C-E configuration with a beta of 100 and a base current of 30 A?

What is the collector current for a C-E configuration with a beta of 100 and a base current of 30 A?
  • A. 30 A
  • B. .3 A
  • C. 3 mA
  • D. 3 MA
  • Correct Answer: Option C

In a C-E configuration, an emitter resistor is used for:

In a C-E configuration, an emitter resistor is used for:
  • A. stabilization
  • B. ac signal bypass
  • C. collector bias
  • D. higher gain
  • Correct Answer: Option A

The Q point on a load line may be used to determine:

The Q point on a load line may be used to determine:
  • A. VC
  • B. VCC
  • C. VB
  • D. IC
  • Correct Answer: Option C

What is the current gain for a common-base configuration where IE = 4.2 mA and IC = 4.0 mA?

What is the current gain for a common-base configuration where IE = 4.2 mA and IC = 4.0 mA?
  • A. 16.80
  • B. 1.05
  • C. 0.20
  • D. 0.95
  • Correct Answer: Option D

If VCC = +18 V, voltage-divider resistor R1 is 4.7 k, and R2 is 1500, what is the base bias voltage?

If VCC = +18 V, voltage-divider resistor R1 is 4.7 k, and R2 is 1500, what is the base bias voltage?
  • A. 8.70 V
  • B. 4.35 V
  • C. 2.90 V
  • D. 0.7 V
  • Correct Answer: Option B

The ends of a load line drawn on a family of curves determine:

The ends of a load line drawn on a family of curves determine:
  • A. saturation and cutoff
  • B. the operating point
  • C. the power curve
  • D. the amplification factor
  • Correct Answer: Option A

The C-B configuration is used to provide which type of gain?

The C-B configuration is used to provide which type of gain?
  • A. voltage
  • B. current
  • C. resistance
  • D. power
  • Correct Answer: Option A

Which is the higher gain provided by a C-E configuration?

Which is the higher gain provided by a C-E configuration?
  • A. voltage
  • B. current
  • C. resistance
  • D. power
  • Correct Answer: Option D

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?

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?
  • A. collector-emitter
  • B. base-emitter
  • C. collector-base
  • D. cathode-anode
  • Correct Answer: Option A

With a PNP circuit, the most positive voltage is probably:

With a PNP circuit, the most positive voltage is probably:
  • A. ground
  • B. VC
  • C. VBE
  • D. VCC
  • Correct Answer: Option A

With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be:

With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be:
  • A. open
  • B. infinite
  • C. low resistance
  • D. high resistance
  • Correct Answer: Option C

When a silicon diode is forward biased, what is VBE for a C-E configuration?

When a silicon diode is forward biased, what is VBE for a C-E configuration?
  • A. voltage-divider bias
  • B. 0.4 V
  • C. 0.7 V
  • D. emitter voltage
  • Correct Answer: Option C
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