MALVINO CHAPTER 9 (MULTISTAGE AMPLIFIERS)

If the input impedance of the
second stage decreases, the
voltage gain of the first stage
will
a. Decrease
b. Increase
c. Remain the same
d. Equal zero

a

If the BE diode of the second
stage opens, the voltage gain of
the first stage will
a. Decrease
b. Increase
c. Remain the same
d. Equal zero

b

If the load resistance of the
second stage opens, the
voltage gain of the first
stage will
a. Decrease
b. Increase
c. Remain the same
d. Equal zero

c

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

b

The total ac emitter
resistance of an emitter
follower equals
a. re'
b. re
c. re + re'
d. RE

c

The input impedance of the
base of an emitter follower
is usually
a. Low
b. High
c. Shorted to ground
d. Open

b

The dc current gain of an
emitter follower is
a. 0
b. = 1
c. Bdc
d. Dependant on re'

c

The ac base voltage of an
emitter follower is across
the
a. Emitter diode
b. DC emitter resistor
c. Load resistor
d. Emitter diode and external ac
emitter resistance

d

The output voltage of an
emitter follower is across the
a. Emitter diode
b. DC collector resistor
c. Load resistor
d. Emitter diode and external ac
emitter resistance

c

If B = 200 and re = 150 ohms,
the input impedance of the
base is
a. 30 kohms
b. 600 ohms
c. 3 kohms
d. 5 kohms

a

The input voltage to an emitter
follower is usually
a. Less than the generator
voltage
b. Equal to the generator
voltage
c. Greater than the generator
voltage
d. Equal to the supply voltage

a

The ac emitter current is
closest to
a. VG divided by re
b. vin divided by re'
c. VG divided by re'
d. vin divided by re

d

The output voltage of an emitter
follower is approximately
a. 0
b. VG
c. vin
d. VCC

c

The output voltage of an
emitter follower is
a. In phase with vin
b. Much greater than vin
c. 180° out of phase
d. Generally much less than vin

a

An emitter-follower buff er is
generally used when
a. RG << RL
b. RG = RL
c. RL << RG
d. RL is very large

c

For maximum power transfer, a
CC amplifier is designed so
a. RG << zin
b. zout >> RL
c. zout << RL
d. zout = RL

d

If a CE stage is directly coupled
to an emitter follower
a. Low and high frequencies will
be passed
b. Only high frequencies will be
passed
c. High-frequency signals will be
blocked
d. Low-frequency signals will be
blocked

a

If the load resistance of an
emitter follower is very large,
the external ac emitter resistance
equals
a. Generator resistance
b. Impedance of the base
c. DC emitter resistance
d. DC collector resistance

c

If an emitter follower has
re' = 10 ohms and re = 90 ohms,
the voltage gain is
approximately
a. 0
b. 0.5
c. 0.9
d. 1

c

An emitter-follower circuit
always makes the source
resistance
a. B times smaller
b. B times larger
c. Equal to the load
d. Zero

a

A Darlington transistor has
a. A very low input impedance
b. Three transistors
c. A very high current gain
d. One VBE drop

c

The amplifi er confi guration
that produces a 180° phase
shift is the
a. CB
b. CC
c. CE
d. All of the above

c

If the generator voltage is 5 mV
in an emitter follower, the output
voltage across the load is
closest to
a. 5 mV
b. 150 mV
c. 0.25 V
d. 0.5 V

a

If the load resistor in Fig. 9-6a
is shorted, which of the following
are diff erent from their
normal values:
a. Only ac voltages
b. Only dc voltages
c. Both dc and ac voltages
d. Neither dc nor ac voltages

a

If R1 is open in an emitter
follower, which of these is
true?
a. DC base voltage is VCC
b. DC collector voltage is zero
c. Output voltage is normal
d. DC base voltage is zero

d

Usually, the distortion in an
emitter follower is
a. Very low
b. Very high
c. Large
d. Not acceptable

a

The distortion in an emitter
follower is
a. Seldom low
b. Often high
c. Always low
d. High when clipping occurs

d

If a CE stage is direct coupled
to an emitter follower, how
many coupling capacitors are
there between the two
stages?
a. 0
b. 1
c. 2
d. 3

a

A Darlington transistor has a
B of 8000. If RE = 1 kohms and
RL= 100 ohms, the input impedance of the base is closest to
a. 8 kohms
b. 80 kohms
c. 800 kohms
d. 8 Mohms

c

The ac emitter resistance of an
emitter follower
a. Equals the dc emitter
resistance
b. Is larger than the load
resistance
c. Is B times smaller than the load
resistance
d. Is usually less than the load
resistance

d

A common-base amplifi er has a
voltage gain that is
a. Much less than one
b. Approximately equal to one
c. Greater than one
d. Zero

c

An application of a common-base
amplifier is when
a. Rsource >> RL
b. Rsource << RL
c. A high current gain is
required
d. High frequencies need to be
blocked

b

A common-base amplifier can
be used when
a. Matching low to high
impedances
b. A voltage gain without a current
gain is required
c. A high-frequency amplifier is
needed
d. All of the above

d

The zener current in a zener
follower is
a. Equal to the output current
b. Smaller than the output current
c. Larger than the output current
d. Prone to thermal runaway

b

In the two-transistor voltage
regulator, the output voltage
a. Is regulated
b. Has much smaller ripple than
the input voltage
c. Is larger than the zener voltage
d. All of the above

d

When troubleshooting multistage
amplifiers, begin by
a. Measuring all dc voltages
b. Signal tracing or signal
injection
c. Taking resistance
measurements
d. Replacing components

b