Bipolar Junction Transistors (BJT)

Q1: Which is beta's current ratio?

A
IC/IB

B
IC/IE

C
IB/IE

D
IE/IB

Q2: Voltage-divider bias provides:

A an unstable Q point

B a stable Q point

C a Q point that easily varies with changes in the transistor's current gain

D a Q point that is stable and easily varies with changes in the transistor’s current gain

Q3: With a PNP circuit, the most positive voltage is probably:

A ground

B
VC

C
VBE

D
VCC

Q4: 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

Q5: 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

Q6: 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

Q7: Three different Q points are shown on a dc load line. The upper Q point represents the:

A minimum current gain

B intermediate current gain

C maximum current gain

D cutoff point

Q8: The symbol hfe is the same as:

A
mca12_1001a1.gif

B
mca12_1001b1.gif

C hi-fi

D
mca12_1001d1.gif

Q9: 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

Q10: A transistor may be used as a switching device or as a:

A fixed resistor

B tuning device

C rectifier

D variable resistor

Q11: Total emitter current is:

A
IE – IC

B
IC + IE

C
IB + IC

D
IB – IC

Q12: The Q point on a load line may be used to determine:

A VC

B VCC

C VB

D IC

Q13: If VCC = +18 V, voltage-divider resistor R1 is 4.7 komega.gif, and R2 is 1500omega.gif, what is the base bias voltage?

A 8.70 V

B 4.35 V

C 2.90 V

D 0.7 V

Q14: In a transistor, collector current is controlled by:

A collector voltage

B base current

C collector resistance

D all of the above

Q15: 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

Q16: The input/output relationship of the common-collector and common-base amplifiers is:

A 270 degrees

B 180 degrees

C 90 degrees

D 0 degrees

Q17: If a transistor operates at the middle of the dc load line, a decrease in the current gain will move the Q point:

A off the load line

B nowhere

C up

D down

Q18: If an input signal ranges from 20–40 mu.gifA (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

Q19: The C-B configuration is used to provide which type of gain?

A voltage

B current

C resistance

D power

Q20: Which is the higher gain provided by a C-E configuration?

A voltage

B current

C resistance

D power

Q21: 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

Q22: What is the collector current for a C-E configuration with a beta of 100 and a base current of 30 mu.gifA?

A
30 mu.gifA

B
.3 mu.gifA

C
3 mA

D 3 MA

Q23:
A current ratio of IC/IE is usually less than one and is called:

A beta

B theta

C alpha

D omega

Q24: To operate properly, a transistor's base-emitter junction must be forward biased with reverse bias applied to which junction?

A collector-emitter

B base-collector

C base-emitter

D collector-base

Q25: 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

Q26:
A transistor has a mca12_1001a1.gif of 250 and a base current, IB, of 20 mu.gif A. The collector current, IC, equals:

A
500 mu.gif A

B 5 mA

C 50 mA

D 5 A

Q27: Often a common-collector will be the last stage before the load; the main function(s) of this stage is to:

A provide voltage gain

B provide phase inversion

C provide a high-frequency path to improve the frequency response

D buffer the voltage amplifiers from the low-resistance load and provide impedance matching for maximum power transfer

Q28: When transistors are used in digital circuits they usually operate in the:

A active region

B breakdown region

C saturation and cutoff regions

D linear region

Q29: In a C-E configuration, an emitter resistor is used for:

A stabilization

B ac signal bypass

C collector bias

D higher gain

Q30: With low-power transistor packages, the base terminal is usually the:

A tab end

B middle

C right end

D stud mount

Q31: A collector characteristic curve is a graph showing:

A
emitter current (IE) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant

B
collector current (IC) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant

C
collector current (IC) versus collector-emitter voltage (VC) with (VBB) base bias voltage held constant

D
collector current (IC) versus collector-emitter voltage (VCC) with (VBB) base bias voltage held constant


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