Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
The feedback pair and the Darlington pair are very similar to each other. One difference between
them is ________.
1)
A)
the feedback pair uses one npn and one pnp transistor
B)
there is no difference between them
C)
the Darlington pair uses one npn and one pnp transistor
D)
there is no similarity between them
Answer:
A
A)
B)
C)
D)
2)
Depending on the configuration of the amplifier, the magnitude of the no–load voltage gain for a
single BJT transistor amplifier typically ranges from ________.
2)
A)
10 to about 10,000
B)
just a little less than 1 to a few hundred
C)
a hundred to about a million
D)
None of the above
Answer:
B
A)
B)
C)
D)
3)
The common–emitter amplifier has ________.
3)
A)
voltage gain and power gain, but no current gain
B)
current gain and voltage gain, but no power gain
C)
current gain and power gain, but no voltage gain
D)
voltage gain, current gain, and power gain
Answer:
D
A)
B)
C)
D)
4)
Determine the equivalent values for and re, given the following h–parameter model values for a
common–emitter amplifier: hie = 1.450 k, hoe = 17.5 µS k, hfe = 125, and hree = 0.4 ×10–3.
4)
A)
125 and 1.450 k
B)
0.4 ×10–3 and 125
C)
1.450 k and 17.5 µS
D)
17.5 µS and 0.4 ×10–3
Answer:
A
A)
B)
C)
D)
1
5)
Given this configuration, determine the input voltage if VS= 40 mV, Rsense = 0.5 k, and the input
current is 20 µA.
5)
A)
40 mV
B)
30 mV
C)
35 mV
D)
55 m
Answer:
B
A)
B)
C)
D)
6)
The approximation that allows superposition to be used to isolate the ac analysis and the dc
analysis of small–signal amplifiers is that the circuit response is ________.
6)
A)
linear
B)
non–linear
C)
dc linear and ac non–linear
D)
dc non–linear and ac linear
Answer:
A
A)
B)
C)
D)
7)
For the common–base configuration, typical values of the output impedance range is ________.
7)
A)
2 to 50
B)
l M to 2 M
C)
100 to 10,000
D)
50 to 1000
Answer:
B
A)
B)
C)
D)
8)
Applying an input signal to one of the inputs of differential amplifier and connecting the other
input to ground, you create a ________ configuration.
8)
A)
common–mode
B)
double–ended
C)
single–ended
D)
None of the above
Answer:
C
A)
B)
C)
D)
2
9)
Replacing a standard transistor with a Darlington pair in an emitter follower causes the voltage
gain to ________.
9)
A)
remain the same
B)
be exactly equal to 1
C)
decrease
D)
increase
Answer:
C
A)
B)
C)
D)
10)
The re transistor model replaces the base–emitter junction with ________.
10)
A)
a constant voltage
B)
the ac resistance of the forward–biased diode at the operating point
C)
an open circuit
D)
a diode
Answer:
B
A)
B)
C)
D)
11)
Determine the input impedance for this amplifier circuit.
11)
A)
re
B)
R1R2re
C)
R1R2
D)
Cannot be determined from the information given
Answer:
B
A)
B)
C)
D)
3
12)
Given the two–port configuration of a BJT amplifier, determine the input voltage if Vs= 18 mV,
Rsense =600,Vo= 3.6 V, and the input current is 20 µA.
12)
A)
12 mV
B)
21.6 m
C)
6 mV
D)
17.994 mV
Answer:
C
A)
B)
C)
D)
13)
Given this configuration, determine the input impedance if VS= 40 mV, Rsense = 0.5 k, and the
input current is 20 µA.
13)
A)
1,500
B)
582 k
C)
1.5 M
D)
5.822 M
Answer:
A
A)
B)
C)
D)
14)
The h12 hybrid parameter is defined as the ________.
14)
A)
open–circuit reverse voltage ratio
B)
open–circuit output admittance
C)
short–circuit input impedance
D)
short–circuit forward current ratio
Answer:
A
A)
B)
C)
D)
15)
For the cascaded amplifier shown here, the output impedance Zo1 is ________ the source resistance
seen by Amplifier 2.
15)
A)
less than
B)
exactly equal to
C)
larger than
D)
much less than
Answer:
B
A)
B)
C)
D)
4
16)
For a two–port system, like a BIT amplifier, the no–load voltage gain ________.
16)
A)
can be less than or equal to the loaded voltage gain
B)
is always equal to the loaded voltage gain
C)
is always greater than the loaded voltage gain
D)
is always less than the loaded voltage gain
Answer:
C
A)
B)
C)
D)
17)
If the resistor in the emitter leg is not bypassed by a capacitor then the input impedance of the small
signal amplifier will ________.
17)
A)
increase
B)
increase in some cases and decrease in other cases
C)
stay the same
D)
decrease
Answer:
A
A)
B)
C)
D)
18)
The voltage gain of a very well–designed common collector amplifier configuration, using a pnp
transistor, is ________.
18)
A)
in the range 0.95 to 0.99
B)
about –0.9
C)
in the range –0.95 to –0.99
D)
about 0.9
Answer:
A
A)
B)
C)
D)
19)
For the cascaded amplifier shown here, the output voltage Vo2 is ________ the input voltage Vi3.
19)
A)
exactly equal to
B)
much larger than
C)
less than
D)
larger than
Answer:
A
A)
B)
C)
D)
5
20)
The h22 hybrid parameter is defined as the ________.
20)
A)
short–circuit forward current ratio
B)
short–circuit input impedance
C)
open–circuit output admittance
D)
open–circuit reverse voltage ratio
Answer:
C
A)
B)
C)
D)
21)
The typical for a Darlington amplifier is ________.
21)
A)
a moderate value in the range of 40 to 400
B)
a very small value in the range 4 to 40
C)
a much higher value in the range of 4000 to about 40,000
D)
a slightly higher value in the range 400 to 4000
Answer:
C
A)
B)
C)
D)
22)
The hybrid parameter that is represented by the name hi is ________.
22)
A)
h21
B)
h22
C)
h12
D)
h11
Answer:
D
A)
B)
C)
D)
23)
The input impedance of a BIT is ________.
23)
A)
a combination of resistive, capacitive, and inductive
B)
capacitive
C)
inductive
D)
resistive
Answer:
D
A)
B)
C)
D)
24)
Given a two–port configuration of a BJT amplifier, determine the no– load voltage gain if Vs= 18
mV, Rsense =600,, Vo= 3.6 V, and the input current is 10 µA.
24)
A)
400
B)
300
C)
200
D)
100
Answer:
C
A)
B)
C)
D)
6
25)
The common–base amplifier has ________.
25)
A)
voltage gain, current gain, and power gain
B)
current gain and power gain, but no voltage gain
C)
voltage gain and power gain, but no current gain
D)
current gain and voltage gain, but no power gain
Answer:
C
A)
B)
C)
D)
26)
For the cascaded amplifier shown here, input impedance Zi2 is ________ the load resistance for
Amplifier 1.
26)
A)
exactly equal to
B)
less than
C)
large than
D)
Cannot be determined from the information provided
Answer:
A
A)
B)
C)
D)
27)
Determine the input impedance for this two–port network when VS= 50 mV, Ii= 20 µA, and
Rsense = 500.
27)
A)
2000
B)
2.0 M
C)
20.0 k
D)
200.0 k
Answer:
A
A)
B)
C)
D)
7
28)
A transistor amplifier has an input signal applied to its emitter terminal and an output signal taken
from its collector terminal. The amplifier is a(n) ________.
28)
A)
common–collector amplifier
B)
common–base amplifier
C)
emitter follower
D)
common–emitter amplifier
Answer:
B
A)
B)
C)
D)
29)
Depending on the configuration of the amplifier, the magnitude of the no–load current gain for a
single BJT transistor amplifier typically ranges from ________.
29)
A)
one to about a thousand
B)
10 to about 10,000
C)
just a little less than 1 to a level that may exceed one hundred
D)
None of the above
Answer:
C
A)
B)
C)
D)
30)
The input impedance of a BJT is ________.
30)
A)
inductive
B)
capacitive
C)
resistive and capacitive
D)
resistive
Answer:
D
A)
B)
C)
D)
31)
A common–emitter amplifier has values of VE= 1.1 V, re= 1 k, and RC= 10 k. What is the
value of the voltage gain for the circuit?
31)
A)
110
B)
484
C)
10
D)
Cannot be determined with the information given
Answer:
D
A)
B)
C)
D)
32)
A fixed–bias common–emitter amplifier has an unbypassed, 1.2 k emitter resistor, and 270 k
base resistor. If re= 5 and = 200, what is the approximate current gain?
32)
A)
565.5
B)
20.55
C)
200
D)
1.05
Answer:
C
A)
B)
C)
D)
8
33)
A fixed–bias common–emitter amplifier has an unbypassed, 1.2 k emitter resistor, and 270 k
base resistor. If re= 5 and = 200, what is the voltage gain?
33)
A)
4.64
B)
24.64
C)
10.3
D)
Cannot be determined with information given
Answer:
D
A)
B)
C)
D)
34)
The base input impedance of a BJT is listed on its spec sheet as ________.
34)
A)
hie
B)
hre
C)
hoe
D)
hje
Answer:
A
A)
B)
C)
D)
35)
The re transistor model replaces the ________ with the junction diode’s ac resistance.
35)
A)
collector–emitter junction
B)
collector–base junction
C)
emitter·base junction
D)
All of the above
Answer:
C
A)
B)
C)
D)
36)
A ________ is a combination of circuit elements, properly chosen, that best approximate the actual
behavior of a semiconductor device under specific operating conditions.
36)
A)
circuit
B)
model
C)
schematic
D)
monolithic IC
Answer:
B
A)
B)
C)
D)
37)
The common·collector amplifier (emitter–follower) has ________.
37)
A)
current gain and voltage gain, but no power gain
B)
voltage gain, current gain, and power gain
C)
voltage gain and power gain, but no current gain
D)
current gain and power gain, but no voltage gain
Answer:
D
A)
B)
C)
D)
9
38)
Amplifier ac input and output voltages are ________.
38)
A)
always 180° out of phase
B)
in phase in all but one amplifier configuration
C)
180° out of phase in all but one amplifier configuration
D)
always in phase
Answer:
B
A)
B)
C)
D)
39)
The hybrid model is used in analysis and design ________.
39)
A)
more than the re model
B)
much more than the re model
C)
less than the re model
D)
equal to the re model
Answer:
C
A)
B)
C)
D)
40)
Calculate the voltage gain for this circuit.
40)
A)
–8.4
B)
–7.92
C)
–137.25
D)
–16.34
Answer:
B
A)
B)
C)
D)
10
41)
Which transistor amplifier configuration has a 180° voltage phase shift from input to output?
41)
A)
common–base
B)
common–emitter
C)
common–collector
D)
None of the above
Answer:
B
A)
B)
C)
D)
42)
The equation that correctly defines one of the hybrid parameters is ________.
42)
A)
Ii=h21 ×Io+h22 ×Vo
B)
Io=h12 ×Vo+h22 ×Vo
C)
Vi=h11 ×Ii+h12 ×Vo
D)
Vo=h11 ×Ii+h21 ×Vi
Answer:
C
A)
B)
C)
D)
43)
When comparing the common emitter and the common collector amplifiers, the input impedance
of the common ________ is much larger and the output impedance of the common ________ is
much smaller.
43)
A)
emitter; collector
B)
collector; emitter
C)
collector; collector
D)
emitter; emitter
Answer:
C
A)
B)
C)
D)
44)
For BJT amplifiers, the no–load voltage gain is ________.
44)
A)
equal to zero
B)
greater than the loaded voltage gain
C)
equal to the loaded voltage gain
D)
less than the loaded voltage gain
Answer:
B
A)
B)
C)
D)
45)
The h–parameter model and the re parameter models are almost identical if the parameter
________ in the h–parameter model is ignored.
45)
A)
hr
B)
hi
C)
ho
D)
hf
Answer:
A
A)
B)
C)
D)
11
46)
The common–base amplifier is characterized as having a relatively ________ input impedance and
relatively ________ output impedance.
46)
A)
high; low
B)
low; high
C)
low; low
D)
high; high
Answer:
B
A)
B)
C)
D)
47)
The h–parameter model uses ________ parameters to describe the equivalent circuit of the BJT
transistor.
47)
A)
five
B)
three
C)
four
D)
two
Answer:
C
A)
B)
C)
D)
48)
If the resistor in the emitter leg is not bypassed by a capacitor then the voltage gain of the small
signal amplifier will ________.
48)
A)
stay the same
B)
decrease
C)
increase in some cases and decrease in other cases
D)
increase
Answer:
B
A)
B)
C)
D)
49)
The output impedance of a BJT is ________.
49)
A)
a combination of resistive, capacitive, and inductive
B)
resistive
C)
capacitive
D)
inductive
Answer:
B
A)
B)
C)
D)
50)
A fixed–bias BJT circuit has values of hFE = 200 and hfe = 120. The ac current gain for the device is
________.
50)
A)
24,000
B)
200
C)
120
D)
320
Answer:
C
A)
B)
C)
D)
12
51)
14. Determine the voltage gain for this amplifier circuit.
51)
A)
RC
re
B)
RCro
rc
C)
RC
re
D)
Cannot be determined from the information given
Answer:
A
A)
B)
C)
D)
52)
To calculate the output impedance the applied signal must be set ________.
52)
A)
equal to the largest value of the input signal
B)
equal to zero
C)
equal to the smallest value of the input signal
D)
equal to a value that is half way between the largest and the smallest
Answer:
B
A)
B)
C)
D)
13
53)
Which of the following circuit conditions indicates that a bypass capacitor is open?
53)
A)
The voltage gain increases significantly.
B)
The presence of a dc voltage at the BJT‘s emitter terminal.
C)
The loss of the ac signal at the base terminal of the BJT.
D)
None of the above
Answer:
D
A)
B)
C)
D)
54)
A given transistor has the following values: hFE = 200, hfe = 120, hie = 5 k, hre = 40, and hoe =
2500 µS. What is the value of ro for the device?
54)
A)
41.7
B)
400
C)
44
D)
25
Answer:
B
A)
B)
C)
D)
55)
The output impedance of a BJT is ________.
55)
A)
resistive
B)
capacitive
C)
resistive and inductive
D)
resistive and capacitive
Answer:
A
A)
B)
C)
D)
56)
The common–emitter configuration has a current gain that is equal to ________.
56)
A)
2
B)
/ 2
C)
D)
20
Answer:
C
A)
B)
C)
D)
57)
If a bypass capacitor opens, the value of re ________.
57)
A)
remains the same
B)
goes to zero
C)
increases
D)
decreases
Answer:
A
A)
B)
C)
D)
14
58)
Which transistor amplifier configuration has a 180° current phase shift from input to output?
58)
A)
common–collector
B)
common–emitter
C)
common–base
D)
None of the above
Answer:
D
A)
B)
C)
D)
59)
As the slope of collector current increases the Early voltage ________.
59)
A)
decreases
B)
decreases very slightly
C)
increases
D)
is unchanged
Answer:
D
A)
B)
C)
D)
60)
Coupling capacitors are chosen to ensure that the values of XC are ________ at the amplifier’s
operating frequency.
60)
A)
large
B)
very small
C)
very large
D)
small
Answer:
B
A)
B)
C)
D)
61)
Bypass capacitors are chosen to ensure that the values of XC are ________ at the amplifier’s
operating frequency.
61)
A)
very small
B)
very large
C)
large
D)
small
Answer:
A
A)
B)
C)
D)
62)
The feedback pair is similar to the Darlington circuit but it is ________.
62)
A)
more used
B)
more complex
C)
simpler to analyze
D)
None of the above
Answer:
B
A)
B)
C)
D)
15
63)
A common–emitter amplifier with voltage divider bias and a bypassed emitter resistance has
values of RC= 10 k, re= 25 , and hFE = 150. What is the value of the voltage gain for the
circuit?
63)
A)
60,000
B)
3750
C)
400
D)
Cannot be determined with the information given
Answer:
C
A)
B)
C)
D)
64)
The h–parameter that is the equivalent of the of a common–emitter circuit is ________.
64)
A)
hre
B)
hie
C)
hfe
D)
hoe
Answer:
C
A)
B)
C)
D)
65)
Determine the current gain for this amplifier circuit.
65)
A)
B)
RC
RC+ro
C)
–R1R2
R1R2+re
D)
Cannot be determined from the information given
Answer:
C
A)
B)
C)
D)
16
66)
Given the two–port configuration of a BJT amplifier, determine the input impedance if Vs= 18 mV,
Rsense =600, Vo= 3.6 V, and the input current is 20 µA.
66)
A)
27 k
B)
1,200
C)
23 k
D)
300
Answer:
D
A)
B)
C)
D)
67)
Determine the output impedance for this amplifier circuit.
67)
A)
RCro
B)
RC
C)
RCro
D)
Cannot be determined from the information given
Answer:
A
A)
B)
C)
D)
68)
The input impedance of the common–emitter configuration is ________.
68)
A)
equal to the transistor beta
B)
inversely related to the transistor beta
C)
directly related to the transistor beta
D)
None of the above
Answer:
C
A)
B)
C)
D)
17
69)
Amplifier ac input and output currents are ________.
69)
A)
always 180°s out of phase
B)
always in phase
C)
in phase in all but one amplifier configuration
D)
180° out of phase in all but one amplifier configuration
Answer:
B
A)
B)
C)
D)
70)
Using the Early voltage, VCEQ and ICQ you can solve for ________.
70)
A)
output impedance
B)
beta AC
C)
beta DC
D)
input impedance
Answer:
A
A)
B)
C)
D)
71)
Calculate the voltage gain for this circuit.
71)
A)
–7.91
B)
–16.34
C)
–8.4
D)
–137.25
Answer:
D
A)
B)
C)
D)
18
72)
An emitter follower has the following values: hie = 3 k, hfe= 150, and hRE = 1.5 k. What is the
voltage gain for the circuit?
72)
A)
0.9925
B)
0.9868
C)
0.5
D)
Cannot be determined with the information given
Answer:
B
A)
B)
C)
D)
19
Answer Key
Testname: C5
1)
A
2)
B
3)
D
4)
A
5)
B
6)
A
7)
B
8)
C
9)
C
10)
B
11)
B
12)
C
13)
A
14)
A
15)
B
16)
C
17)
A
18)
A
19)
A
20)
C
21)
C
22)
D
23)
D
24)
C
25)
C
26)
A
27)
A
28)
B
29)
C
30)
D
31)
D
32)
C
33)
D
34)
A
35)
C
36)
B
37)
D
38)
B
39)
C
40)
B
41)
B
42)
C
43)
C
44)
B
45)
A
46)
B
47)
C
48)
B
49)
B
50)
C
Answer Key
Testname: C5
51)
A
52)
B
53)
D
54)
B
55)
A
56)
C
57)
A
58)
D
59)
D
60)
B
61)
A
62)
B
63)
C
64)
C
65)
C
66)
D
67)
A
68)
C
69)
B
70)
A
71)
D
72)
B