Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
A BJT has measured dc current values of IB= 0.1 mA and IC= 8.0 mA. When IB is varied by 100
µA, IC changes by 10 mA. What is the value of the ac for this device?
1)
A)
800
B)
100
C)
10
D)
80
Answer:
B
A)
B)
C)
D)
2)
Which of the following expressions is true?
2)
A)
ac=IC
IE where VCB is constant
B)
ac=IC
IE
C)
ac=IC
IB
D)
ac=IC
IB where VCE is constant
Answer:
D
A)
B)
C)
D)
3)
A BJT has measured dc current values of IB= 1 mA and IC= 80 mA. When IB is varied by 100 µA,
IC changes by 10 mA. What is the value of dc for the device?
3)
A)
80
B)
10
C)
800
D)
100
Answer:
A
A)
B)
C)
D)
4)
Moore’s Law states that transistor count in an integrated circuit will double every ________ years.
4)
A)
4
B)
8
C)
6
D)
2
Answer:
D
A)
B)
C)
D)
1
5)
In the active region, the base–emitter junction ________.
5)
A)
is forward–biased while the base–collector junction is reversed–biased
B)
and the base–collector junctions are both forward–biased
C)
and the base–collector junctions are both reverse–biased
D)
is reverse–biased while the base–collector junction is forward–biased
Answer:
A
A)
B)
C)
D)
6)
A given BJT has an emitter current of 15 mA and a collector current of 14.95 mA. What is the exact
value of ?
6)
A)
300
B)
250
C)
1.003
D)
299
Answer:
D
A)
B)
C)
D)
7)
Which of the following expressions is true?
7)
A)
dc=IC
IB
B)
dc=IC
IE
C)
dc=IC
IB where VCE is constant
D)
dc=IC
IE where VCB is constant
Answer:
D
A)
B)
C)
D)
8)
A given BJT has an emitter current of 12 mA and a base current of 600 µA. What is the value of
dc?
8)
A)
20
B)
19
C)
21
D)
200
Answer:
B
A)
B)
C)
D)
2
9)
Which of the following biasing combinations is not normally associated with one of the three
transistor operating regions’?
9)
A)
E–B junction = reverse, C–B junction = forward
B)
E–B junction = forward, C–B junction = reverse
C)
E–B junction = reverse, C–B junction = reverse
D)
All of the above
Answer:
A
A)
B)
C)
D)
10)
This is the symbol for a ________.
10)
A)
pnn–type BJT
B)
npn–type BJT
C)
npp–type BJT
D)
pnp–type BJT
Answer:
D
A)
B)
C)
D)
11)
In the saturation region, the base–emitter junction ________.
11)
A)
is reversed–biased while the base–collector junction is forward–biased
B)
is forward–biased while the base–collector junction is reversed–biased
C)
and the base–collector junctions are both forward–biased
D)
and the base–collector junctions are both reverse–biased
Answer:
C
A)
B)
C)
D)
12)
A given BJT has an alpha of 0.9985 and a collector current of 15 mA. What is the value of base
current?
12)
A)
15.15 mA
B)
15 mA
C)
14.85 mA
D)
None of the above
Answer:
D
A)
B)
C)
D)
3
13)
As ________ decreases the noise figure increases.
13)
A)
freqency
B)
source resistance
C)
collector current
D)
all of the above
Answer:
A
A)
B)
C)
D)
14)
Which of the following is true for this BJT circuit?
14)
A)
The base–emitter junction is forward–biased and the collector–base junction is
reversed–biased.
B)
The base–emitter and collector–base junctions are both forward–biased.
C)
The base–emitter junction is reverse–biased and the collector–base junction is
forward–biased.
D)
The base–emitter and collector–base junctions are both reverse–biased.
Answer:
A
A)
B)
C)
D)
15)
VCE is measured ________.
15)
A)
from the collector terminal to the emitter terminal
B)
from the collector–emitter junction to ground
C)
from the emitter terminal to ground
D)
None of the above
Answer:
A
A)
B)
C)
D)
4
16)
In a small–signal transistor, the typical range of the parameter is ________.
16)
A)
between 0 and 100
B)
large and in the range of about 50 to 400
C)
almost equal to 100 but always less than 100 (90 to 100)
D)
greater than 100
Answer:
B
A)
B)
C)
D)
17)
The common–base, short–circuit, amplification factor is better known as ________.
17)
A)
ac
B)
ac
C)
dc
D)
dc
Answer:
B
A)
B)
C)
D)
18)
When a BJT is operating in the saturation region the voltage drop from the collector to the emitter
VCE is approximately equal to ________.
18)
A)
the emitter voltage
B)
the collector supply voltage
C)
zero (about 0.3 Volts)
D)
the collector current times the collector resistor
Answer:
C
A)
B)
C)
D)
19)
For the CB configuration breakdown occurs when ________ is too high but in the CC configuration
too high a ________ results in breakdown.
19)
A)
VCB, VBE
B)
VBE, VCE
C)
VBE, VCE
D)
VCB, VCE
Answer:
D
A)
B)
C)
D)
20)
BJTs are commonly used as ________.
20)
A)
series damper circuits
B)
the primary components in amplifiers
C)
the primary components in rectifiers
D)
All of the above
Answer:
B
A)
B)
C)
D)
5
21)
Identify the terminals on this BJT.
21)
A)
1 = emitter, 2 = collector, 3 = base
B)
1 = base, 2 = emitter, 3= collector
C)
1 = collector, 2 = emitter, 3 = base
D)
1 = collector, 2 = base, 3 = emitter
Answer:
C
A)
B)
C)
D)
22)
Which transistor amplifier configuration is the most commonly used?
22)
A)
common–base
B)
common–collector
C)
common–emitter
D)
None of these are used more often than the others.
Answer:
C
A)
B)
C)
D)
23)
In most cases, which two of the three BJT terminal currents are approximately equal in value?
23)
A)
collector current and emitter current
B)
emitter current and base current
C)
collector current and base current
D)
All currents are approximately equal.
Answer:
A
A)
B)
C)
D)
24)
In the cut–off region, the base–emitter junction ________.
24)
A)
is reversed–biased while the base–collector junction is forward–biased
B)
and the base–collector junctions are both reverse–biased
C)
is forward–biased while the base–collector junction is reverse–biased
D)
and the base–collector junctions are both forward–biased
Answer:
B
A)
B)
C)
D)
6
25)
For basic operation of a transistor the collector–base junction is ________ biased.
25)
A)
not
B)
semi–
C)
forward–
D)
reverse–
Answer:
D
A)
B)
C)
D)
26)
For a given BJT, = 400. What is the value of for the device?
26)
A)
1.00
B)
0.002
C)
0.9975
D)
1.0025
Answer:
C
A)
B)
C)
D)
27)
Which of the following is true for this BJT circuit?
27)
A)
The base–emitter and collector–base junctions are both reverse–biased.
B)
The base–emitter junction is reverse–biased and the collector–base junction is
forward–biased.
C)
The base–emitter junction is forward–biased and the collector–base junction is
reversed–biased.
D)
The base–emitter and collector–base junctions are both forward–biased.
Answer:
C
A)
B)
C)
D)
28)
A BJT has measured dc current values of IB= 1 mA and IC= 80 mA. When IB is varied by 100 µA,
IC changes by 10 mA. What is the value of ac for the device?
28)
A)
10
B)
100
C)
80
D)
800
Answer:
B
A)
B)
C)
D)
7
29)
This is the symbol for a ________.
29)
A)
ppn–type BJT
B)
pnn–type BJT
C)
pnp–type BJT
D)
npn–type BJT
Answer:
D
A)
B)
C)
D)
30)
A BJT has measured dc current values of IB= 0.1 mA and IC= 8.0 mA. When IB is varied by 100
µA, IC changes by 10 mA. What is the value of the dc for this device?
30)
A)
10
B)
100
C)
800
D)
80
Answer:
D
A)
B)
C)
D)
31)
The condition where an increase in bias current will not cause further increases in collector current
is called ________.
31)
A)
saturation
B)
cutoff
C)
active operation
D)
All of the above
Answer:
A
A)
B)
C)
D)
32)
Which of the following expressions is true?
32)
A)
dc=IC
IE
B)
dc=IC
IB where VCE is constant
C)
dc=IC
IB
D)
dc=IC
IE where VCB is constant
Answer:
C
A)
B)
C)
D)
33)
For basic operation of a transistor the base–emitter junction is ________ biased.
33)
A)
forward–
B)
reverse–
C)
semi–
D)
not
Answer:
A
A)
B)
C)
D)
8
34)
When a transistor is in saturation VCE is approximately equal to ________.
34)
A)
collector current times collector resistor
B)
collector supply voltage
C)
0.3 Volts
D)
emitter voltage
Answer:
C
A)
B)
C)
D)
35)
When a BJT is operating in the active region, the voltage drop from the base to the emitter VBE is
approximately equal to the ________.
35)
A)
diode drop (about 0.7 V)
B)
emitter voltage
C)
base current times the base resistor
D)
base bias voltage
Answer:
A
A)
B)
C)
D)
36)
The common–emitter, forward–current, amplification factor is better known as ________.
36)
A)
dc
B)
ac
C)
ac
D)
dc
Answer:
B
A)
B)
C)
D)
37)
In a small–signal transistor, the typical range of the parameter is ________.
37)
A)
almost equal to 1 but always less than 1 (0.9 to 1.0)
B)
greater than 1
C)
almost equal to 1 but always greater than 1 (1.0 to 1.1)
D)
between 0 and 1
Answer:
A
A)
B)
C)
D)
38)
A given transistor has ratings of maximum collector current equal to 200 mA and a beta that varies
between 150 and 200. What is the maximum allowable value of base current for the device?
38)
A)
4 mA
B)
1 mA
C)
1.33 mA
D)
None of the above
Answer:
B
A)
B)
C)
D)
9
39)
Which of the following expressions is true?
39)
A)
dc=IC
IB where VCE is constant
B)
dc=IC
IE
C)
dc=IC
IE where VCB is constant
D)
dc=IC
IB
Answer:
B
A)
B)
C)
D)
40)
The output or collector characteristics for a common base transistor amplifier shows that as a first
approximation the relation between IE and IC in the active region is given by ________.
40)
A)
IEIC
B)
IE>> IC
C)
IE=IC
D)
IE<< IC
Answer:
A
A)
B)
C)
D)
41)
Why is the arrow on the BJT schematic symbol important?
41)
A)
It identifies the emitter terminal and the type of BJT.
B)
It identifies the base terminal and the type of BJT.
C)
It identifies the collector terminal and the type of BJT.
D)
None of the above
Answer:
A
A)
B)
C)
D)
42)
is the ratio of ________.
42)
A)
collector current to base current
B)
base current to collector current
C)
collector current to emitter current
D)
emitter current to collector current
Answer:
A
A)
B)
C)
D)
10
Answer Key
Testname: C3
1)
B
2)
D
3)
A
4)
D
5)
A
6)
D
7)
D
8)
B
9)
A
10)
D
11)
C
12)
D
13)
A
14)
A
15)
A
16)
B
17)
B
18)
C
19)
D
20)
B
21)
C
22)
C
23)
A
24)
B
25)
D
26)
C
27)
C
28)
B
29)
D
30)
D
31)
A
32)
C
33)
A
34)
C
35)
A
36)
B
37)
A
38)
B
39)
B
40)
A
41)
A
42)
A