Blake Chapter 2 MCQ With Answers

Blake Chapter 2



  1.   The time it takes a charge carrier to cross from the emitter to the collector is called:
a.
base time
c.
charge time
b.
transit time
d.
Miller time


ANS:   B

  2.   A real capacitor actually contains:
a.
capacitance and resistance only
c.
capacitance, inductance, and resistance
b.
capacitance and inductance only
d.
reactance only


ANS:   C

  3.   Bypass capacitors are used to:
a.
remove RF from non-RF circuits
c.
neutralize amplifiers
b.
couple RF around an amplifier
d.
reduce the Miller effect


ANS:   A

  4.   A resonant circuit is:
a.
a simple form of bandpass filter
c.
both a and b
b.
used in narrowband RF amplifiers
d.
none of the above


ANS:   C

  5.   Loading down a tuned-circuit amplifier will:
a.
raise the Q of the tuned circuit
c.
"multiply" the Q
b.
lower the Q of the tuned circuit
d.
have no effect on Q


ANS:   B

  6.   The "Miller Effect" can:
a.
cause an amplifier to oscillate
c.
reduce the bandwidth of an amplifier
b.
cause an amplifier to lose gain
d.
all of the above


ANS:   D

  7.   The Miller Effect can be avoided by:
a.
using a common-emitter amplifier
c.
increasing the Q of the tuned circuit
b.
using a common-base amplifier
d.
it cannot be avoided


ANS:   B

  8.   In a BJT, the Miller Effect is due to:
a.
inductance of collector lead
c.
base-to-emitter capacitance
b.
collector-to-emitter capacitance
d.
base-to-collector capacitance


ANS:   D

  9.   In RF amplifiers, impedance matching is usually done with:
a.
RC coupling
c.
direct coupling
b.
transformer coupling
d.
lumped reactance


ANS:   B

10.   Neutralization cancels unwanted feedback by:
a.
adding feedback out of phase with the unwanted feedback
b.
bypassing the feedback to the "neutral" or ground plane
c.
decoupling it
d.
none of the above


ANS:   A

11.   For a "frequency multiplier" to work, it requires:
a.
a nonlinear circuit
b.
a linear amplifier
c.
a signal containing harmonics
d.
an input signal that is an integer multiple of the desired frequency


ANS:   A

12.   A sinusoidal oscillation from an amplifier requires:
a.
loop gain equal to unity
b.
phase shift around loop equal to 0 degrees
c.
both a and b, but at just one frequency
d.
none of the above


ANS:   C

13.   The conditions for sinusoidal oscillation from an amplifier are called:
a.
the loop-gain criteria
c.
the Bode criteria
b.
the Hartley criteria
d.
the Barkhausen criteria


ANS:   D

14.   The Hartley oscillator uses:
a.
a tapped inductor
c.
an RC time constant
b.
a two-capacitor divider
d.
a piezoelectric crystal


ANS:   A

15.   The Colpitts VFO uses:
a.
a tapped inductor
c.
an RC time constant
b.
a two-capacitor divider
d.
a piezoelectric crystal


ANS:   B

16.   The Clapp oscillator is:
a.
a modified Hartley oscillator
c.
a type of crystal-controlled oscillator
b.
a modified Colpitts oscillator
d.
only built with FETs


ANS:   B

17.   A varactor is:
a.
a voltage-controlled capacitor
c.
used in tuner circuits
b.
a diode
d.
all of the above


ANS:   D

18.   Crystal-Controlled oscillators are:
a.
used for a precise frequency
b.
used for very low frequency drift (parts per million)
c.
made by grinding quartz to exact dimensions
d.
all of the above


ANS:   D

19.   If two signals, Va = sin(wat) and Vb = sin(wbt), are fed to a mixer, the output:
a.
will contain w1 = wa + wb and w2 = wawb
b.
will contain w1 = wa / wb and w2 = wb / wa
c.
will contain w = (wa + wb ) / 2
d.
none of the above


ANS:   A

20.   In a balanced mixer, the output:
a.
contains equal (balanced) amounts of all input frequencies
b.
contains the input frequencies
c.
does not contain the input frequencies
d.
is a linear mixture of the input signals


ANS:   C

21.   "VFO" stands for:
a.
Voltage-Fed Oscillator
c.
Varactor-Frequency Oscillator
b.
Variable-Frequency Oscillator
d.
Voltage-Feedback Oscillator


ANS:   B

22.   A "frequency synthesizer" is:
a.
a VCO phase-locked to a reference frequency
b.
a VFO with selectable crystals to change frequency
c.
a fixed-frequency RF generator
d.
same as a mixer


ANS:    A

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