Blake Chapter 3 MCQ With Answers

Blake Chapter 3

  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, V_a = sin(w_at) and V_b = sin(w_bt), are fed to a mixer, the output:

a.	will contain w1 = wa + wb and w2 = wa – wb
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