SEMICONDUCTORS 1. A silicon diode measures a low value of resistance with the meter leads in both positions. The trouble, if any, is
5.
As the the forward forward current through through a silicon diode increases, the internal resistance A.
increases.
B.
decreases.
C.
remains the same.
A.
the diode is open.
B.
the diode is shorted to ground.
Answer: Option B
C.
the diode is internally shorted.
6.
D.
the diode is working correctly.
Answer: Option C
2.
Single-element semiconductors are characterized characterized by atoms with ____ valence electrons.
The movement of free electrons in a conductor is called A.
voltage.
B.
current.
C.
recombination.
D.
equilibrium.
Answer: Option B
A.
3
B.
4
C.
5
A.
decreases
D.
2
B.
remains constant
E.
none of the above
C.
increases
Answer: Option B
7. For a forward-biased forward-biased diode, d iode, the barrier potential ________ as temperature increases. increases.
Answer: Option A 8. The wide end arrow on a schematic indicates the ________ of a diode.
3.
Under normal conditions a diode conducts current when it is
ground
B.
direction of electron flow
A.
reverse-biased.
C.
cathode
B.
forward-biased.
D.
anode
C.
avalanched.
D.
saturated.
Answer: Option B
4.
A.
A diode conducts when it is forward-biased, forward-biased, and the anode is connected to th e ________ through a limiting resistor. A.
positive supply
B.
negative supply
C.
cathode
D.
anode
Answer: Option A
Answer: Option D 9. An n-type n -type semiconductor material material A.
is intrinsic.
B.
has trivalent impurity atoms added.
C.
has pentavalent impurity atoms added.
D.
requires no doping.
Answer: Option C Explanation: N-type Semiconductor : An intrinsic semiconductor semiconductor material material is a poor conductor. When a small amount of pentavalent impurity is added to t he intrinsic material its conductivity rises sharply. This material formed after the addition of pentavalent impurity to the intrinsic semiconductor material is called N-type material. Addition of small amount of pentavalent pentavalent atoms in the
intrinsic material provides large numb er of free electrons electrons for conduction. 10. For a forward-biased diode, as temperature is ________, the forward forward current ________ for a given value of forward voltage.
C.
a forward-biased silicon diode.
D.
a reverse-biased germanium diode.
Answer: Option B
A.
decreased, increases
B.
increased, increases
C.
increased, decreases
A.
open, short
D.
decreased, decreases
B.
short, open
C.
open, open
D.
short, short
Answer: Option B
11. Which statement best describes an insulator?
15. An ideal diode presents presents a(n) ________ when when reversed-biased and a(n) ________ when forwardbiased.
Answer: Option A
A. A material material with many free free electrons. B. A material material doped to have some free free electrons. C. A material material with few free electrons. D.
No description fits.
Answer: Option C
12. Effectively, Effectively, how many valence electrons are there there in each atom within a silicon crystal? A.
2
B.
4
C.
8
D.
16
Answer: Option C
13. The boundary between between p-type material and n-type material is called
16. A reverse-biased reverse-biased diode has the ________ ________ connected to the positive side of the source, and th e ________ connected to the negative negative side of the source. A.
cathode, anode
B.
cathode, base
C.
base, anode
D.
anode, cathode
Answer: Option A
17. What types of impurity atoms atoms are added to increase the number of conduction-band electrons in intrinsic silicon? A.
bivalent
B.
octavalent
C.
pentavalent
A.
a diode.
D.
trivalent
B.
a reverse-biased diode.
E.
none of the above
C.
a pn junction. junction.
D.
a forward-biased diode.
Answer: Option C
14. You have an unknown unknown type of diode in a circuit. circuit. You measure the voltage across it and find it to b e 0.3 V. The diode might be A. B.
a silicon diode. a germanium diode.
Answer: Option C
18. What factor(s) do(es) do(es) the barrier potential of a pn unction depend on? A.
type of semiconductive material
B.
the amount of doping
C.
the temperature
D.
all of the above
E.
type of semiconductive material and the amount of doping but not the temperature
C.
that impurities are added to decrease the resistance of the material.
D.
that all impurities are removed to get pure silicon.
Answer: Option D
19. An atom is made up of
Answer: Option C
A.
protons.
B.
neutrons.
C.
electrons.
A.
0.3 V.
D.
all of the above
B.
1.7 V.
Answer: Option D
20. Reverse breakdown breakdown is a condition in which which a diode A.
is subjected to a large reverse voltage.
B.
is reverse-biased and there is a small leakage current.
C.
has no current flowing at all.
D.
is heated up by large amounts of current in the forward direction.
Answer: Option A
21. There is a small amount of current current across the barrier of a reverse-biased diode. This current is called A.
forward-bias forward-bias current.
B.
reverse breakdown current.
C.
conventional current.
D.
reverse leakage current.
Answer: Option D
22. As the forward current through a silicon silicon diode increases, the voltage across the diode A.
increases to a 0.7 V maximum.
B.
decreases.
C.
is relatively constant.
D.
decreases and then increases. increases.
Answer: Option C
23. Doping of a semiconductor material means means A.
B.
that a glue-type substance is added to hold the material together. that impurities are added to increase the resistance of the material.
24. The forward forward voltage across a conducting silicon diode is about
C. –0.7 V. D.
0.7 V.
Answer: Option D Explanation: No answer description available for this question. Let us discuss. discuss.
25. The most common type of diode failure is a(n) ________. A.
open
B.
short
C.
resistive
Answer: Option A
26. What occurs when a conduction-band conduction-band electron electron loses energy and falls back into a h ole in the valence band? A.
doping
B.
recombination
C.
generation
Answer: Option B
27. The maximum maximum number of electrons in each shell of an atom is A.
2.
B.
2n 2 where n is the number of the shell.
C.
4.
D.
8.
Answer: Option B
28. A silicon diode is forw forward-biased. ard-biased. You measure the voltage to ground from the anode at ________, and the voltage from the cathode to ground at ________.
A.
0 V, 0.3 V
B.
2.3 V, 1.6 V
C.
1.6 V, 2.3 V
D.
3.
The Schottky diode is used A.
in high-power circuits.
B.
in circuits requiring negative resistance.
C.
in very fast-switching circuits.
D.
in power supply rectifiers.
0.3 V, 0 V
Answer: Option B Explanation:
For silicon diodes, the bu ilt-in potential is approximately 0.7 V. Thus, if an external external current is passed through the diode, about 0.7 V will will be developed across the diode such that the P-doped region is positive with respect to the N-doped region and the diode is said to be "turned on" as it has a forward forward bias.
Answer: Option C
4.
Therefore, Therefore, 2.3 V - 1.6 V = 0.7 V. Hence the answer is correct.
You have have an application application for for a diode to be used in in a tuning circuit. A type of diode to use might be A.
an LED.
B.
a Schottky diode.
C.
a Gunn diode.
D.
a varactor.
Answer: Option D
29. The term bias in electronics usually means A.
the value of ac voltage in the signal.
B.
the condition of current through a pn junction.
C.
the value of dc voltages for the device to operate properly.
D.
the status of the diode.
5. Refer to this figure. Which symbol is correct for an LED?
Answer: Option C
A.
a
B.
b
C.
c
D.
d
E.
e
SPECIAL-PURPOSE DIODE
1.
Schottky diodes are also known as A.
PIN diodes.
B.
hot carrier diodes.
C.
step-recovery diodes.
D.
tunnel diodes.
Answer: Option A Answer: Option B
2.
6.
Refer to this figure. If V IN increases, I Z will
Zener diodes with with breakdown breakdown voltages voltages less than 5 V operate predominantly in what type of breakdown? breakdown? A.
avalanche
B.
zener
C.
varactor
D.
Schottky
Answer: Option B
A.
increase.
B.
decrease.
C.
remain the same.
10. Refer to this figure. Identify the Schottky diode.
Answer: Option A
7.
What kind kind of diode is is formed formed by joining a doped semiconductor region with a m etal? A.
laser
B.
tunnel
A.
a
C.
pin
B.
b
D.
Schottky
C.
c
D.
d
E.
e
Answer: Option D
8. Refer to this figure. Which symbol is correct for a zener diode?
Answer: Option E
11. LEDs are made out out of
A.
a
B.
b
C.
c
D.
d
E.
silicon.
B.
germanium.
C.
gallium.
D.
silicon and germanium, but not g allium.
Answer: Option C
12. The normal operating operating region for for a zener diode is is the A.
forward-bias forward-bias region.
B.
reverse-bias region.
C.
zero-crossing region.
D.
reverse-breakdown reverse-breakdown region.
e
Answer: Option B
9.
A.
Which diode employs graded doping? A.
zener
B.
LED
C.
tunnel
D.
step-recovery
Answer: Option D
13. Refer to this figure. If V IN attempts to increase, increase, VR will
Answer: Option D
A.
increase.
B.
decrease.
C.
remain the same.
Answer: Option A
14. An LED is forward-biase forward-biased. d. The diode should be on, but no light is sh owing. owing. A possible trouble might be A.
the diode is open.
B.
the series resistor is too small.
C.
none. The diode should be off if forwardbiased.
D.
the power supply voltage is too high.
Answer: Option A
15. A 6.2 V zener is rated at 1 watt. The The maximum safe current the zener can carry is A.
1.61 A.
B.
161 mA.
C.
16.1 mA.
D.
1.61 mA.
Answer: Option B
16. Refer to this figure. Find the tunnel diode symbol.
A.
remain the same, increase
B.
decrease, remain the same
C.
increase, remain the same
D.
remain the same, decrease
Answer: Option D
18. The process process of emitting photons from from a semiconductive material is called A.
photoluminescence.
B.
gallium arsenide.
C.
electroluminescence.
D.
gallium phosphide.
Answer: Option C
19. An 8.2 V zener has a resistance resistance of 5 . The actual voltage across its terminals when the current is 25 mA is
A.
a
B.
b
C.
c
D.
d
E.
e
A.
8.2 V.
B.
125 mV.
C.
8.325 V.
D.
8.075 V.
Answer: Option C
nswer: Option D
17. Refer to this figure. If the load load current increases, IR will ________ and IZ will ________.
20. What diode operates operates only with majority majority carriers? carriers? A.
laser
B.
tunnel
C.
Schottky
D.
step-recovery
Answer: Option C
21. Refer to this figure. Which symbol is correct for a photodiode?
C.
remain the same.
Answer: Option B
25. Zener diodes with with breakdown voltages voltages greater than 5 V operate predominantly in what type of breakdown? A.
avalanche
A.
a
B.
zener
B.
b
C.
varactor
C.
c
D.
Schottky
D.
d
E.
e
nswer: Option C
22. What type of diode maintains a constant current? current? A.
LED
B.
zener
C.
current regulator
D.
pin
E.
none of the above
Answer: Option C
23. What diode is used in seven-segment seven-segment displays?
Answer: Option A
26. Back-to-back varactor varactor diodes are used for what reason? A.
over-voltage protection
B.
a wider tuning range
C.
to eliminate harmonic d istortion
D.
no reason; only zeners are used in a back-toback configuratio con figuration n
Answer: Option C
27. A tunnel diode diode is used A.
in high-power circuits.
B.
in circuits requiring negative resistance.
A.
zener
C.
in very fast-switching circuits.
B.
LED
D.
in power supply rectifiers.
C.
laser
D.
Schottky
Answer: Option B
Answer: Option B
28. What type of diode is commonly used in electronic electronic tuners in TVs? A.
varactor
B.
Schottky
C.
LED
D.
Gunn
24. Refer to this figure. figure. If V IN decreases, IR will
Answer: Option A
29. A laser diode normally emits A.
coherent light.
A.
increase.
B.
monochromatic light.
B.
decrease.
C.
coherent and monochromatic light.
D.
neither coherent nor monochromatic light.
3.
Refer to this figure. If V CE = 0.2 V, I C(sat) is:
Answer: Option C
30. A varactor is a pn junction diode that always always operates in ________-bias and is doped to ________ the inherent capacitance capacitance of the depletion depletion region. A.
forward, maximize
B.
reverse, maximize
C.
reverse, minimize
D.
forward, minimize
Answer: Option B
BIPOLAR JUNCTION TRANSISTORS 1.
Refer to this figure. Determine the minimum minimum value value of of IB that will produce saturation.
A.
0.05 mA
B.
2.085 mA
C.
1.065 mA
D.
7.4 mA
Answer: Option B
4.
What is is the ratio of I C to IB? A. B. C. D.
DC
hFE DC
either
DC or
hFE, but not
DC
Answer: Option D A.
0.25 mA
B.
5.325
A
C.
1.065
A
D.
10.425
5.
A
Answer: Option D
2.
A transistor amplifier amplifier has a voltage voltage gain of 100. If the input voltage is 75 mV, the output voltage is: A.
1.33 V
B.
7.5 V
C.
13.3 V
D.
15 V
Answer: Option B
For normal operation of a pnp BJT, the base must must be ________ with respect to the em itter and ________ with respect to the the collector. collector. A.
positive, positive, negative n egative
B.
positive, positive, positive
C.
negative, positive
D.
negative, negative
Answer: Option C
6.
Refer to this figure. The value of V BC is:
10. A certain transistor has IC = 15 mA and I B = 167 A;
DC is:
A.
15
B.
167
C.
0.011
D.
90
Answer: Option D
11. Refer to this figure. The value value of VCE is: A.
9.2 V
B.
9.9 V
C. –9.9 V D. –9.2 V Answer: Option D
7.
When a transistor is used used as a switch, it is stable in which two distinct regions? A.
saturation and active
B.
active and cutoff
C.
saturation and cutoff
D.
none of the above
Answer: Option C
8.
The term BJT is short for A.
base junction transistor.
B.
binary junction transistor. transistor.
C.
both junction transistor.
D.
bipolar junction transistor.
A.
9.9 V
B.
9.2 V
C.
0.7 V
D.
19.3 V
Answer: Option A
12.
Answer: Option D
What does
DC vary
A.
IC
B.
ºC
C.
both IC and ºC
D.
IC, but not ºC
with?
Answer: Option C
9.
For a silicon transistor, when a base-emitter junction is forward-biased, it has a nominal voltage drop of A.
0.7 V.
B.
0.3 V.
C.
0.2 V.
D.
VCC.
Answer: Option A
13.
A BJT has an IB of 50 A.
375 mA
B.
37.5 mA
C.
3.75 mA
D.
0.375 mA
Answer: Option C
A and a
DC of
75; I C is:
14. Refer to this figure. The value value of VBE is:
D.
150 k
Answer: Option A
17.
The value of
DC
A.
is fixed for any particular transistor.
B.
varies with temperature.
C.
varies with I C.
D.
varies with temperature and IC.
Answer: Option D A.
0.6 V
B.
0.7 V
C.
1.2 V
A.
hre.
D.
0.079 V
B.
hFE.
Answer: Option B
C.
IC.
D.
VCE.
18.
15. What are the two two types of bipolar bipolar junction transistors? A.
npn and pnp
B.
pnn and nnp
DC as
Answer: Option B
19. What is the ratio ratio of IC to IE?
C.
ppn and nnp
D.
pts and stp
A. B.
Answer: Option A
16.
A transistor data sheet sheet usually identifies
C. D.
In this circuit DC = 100 and V IN = 8 V. The value of RB that will produce saturation is:
92 k
B.
9.1 M
C.
100 k
DC /
(
DC +
1)
DC
either
DC /
(
DC +
1) or
DC,
but not
DC
Answer: Option D
20.
A.
DC
Refer to this figure. The value of VIN = 8 V. Determine I C(sat).
A.
18 mA
DC =
100 and
B.
7.92 mA
A.
3.5 V
C.
1.8 mA
B.
28.57 V
D.
8
C.
4.375 mV
D.
4.375 V
A
Answer: Option B
Answer: Option D
21. Which of the following following is true for an npn or pnp transistor?
26. What is (are) (are) general-purpose/small-signal general-purpose/small-signal transistors case type(s)?
A.
IE = IB + IC
B.
I B = I C+ I E
A.
TO-18
C.
IC = IB + IE
B.
TO-92
D.
none of the above
C.
TO-39
D.
TO-52
E.
all of the above
Answer: Option A
22. What is the order of doping, from from heavily to lightly doped, for each region?
Answer: Option E
A.
base, collector, emitter
B.
emitter, collector, base
C.
emitter, base, collector
A.
opens or shorts internal to the transistor
D.
collector, collector, emitter, base
B.
open bias resistor(s)
C.
external opens and shorts on the circuit board
D.
all of the above
Answer: Option B
23. In what range of voltages is the transistor in in the linear region of its operation? A.
0 < V CE
B.
0.7 < VCE < VCE(max)
C.
VCE(max) > VCE
D.
none of the above
Answer: Option B
24. The magnitude of dark current in a phototransistor phototransistor usually falls in what range? A.
mA
B.
μA
C.
nA
D.
pA
Answer: Option C
25. A 35 mV signal is applied to the base of a properly biased transistor with an r'e = 8 and RC = 1 k . The output signal voltage at the collector is:
27. What is (are) common fault(s) in in a BJT-based circuit?
Answer: Option D
28. The dc load line on a family of collector collector characteristic characteristic curves of a transistor shows the A.
saturation region.
B.
cutoff region.
C.
active region.
D.
all of the above
Answer: Option D
29. Refer to this figure. Determine Determin e the minimum value of VIN from the th e following following that th at will saturate saturate this transistor.
A.
Current tracer
B.
Digital display meter (DDM)
C.
Ohmmeter (VOM)
D. All of the above above Answer: Option D
4. A.
13.21 V
B.
12.51 V
C.
0.7 V
D.
9.4 V
For what kind of amplifications amplifications can the active region of the common-emitter configuration configuration be used? A.
Voltage
B.
Current
C.
Power
Answer: Option A D. All of the above above Answer: Option D
BJT DEVICES 1.
How much is the base-to-emitter voltage of a transistor in the "on" st ate? A. B. C. D.
5.
0V
In the active region, while the collector-base collector-base junction is ________-biased, the base-emitter is ________biased. A.
forward, forward, forward forward
B.
forward, forward, reverse
C.
reverse, forward
D.
reverse, reverse
0.7 V 0.7 mV Undefined
Answer: Option B
Answer: Option C
2.
How many layers layers of material material does a transistor have? have? A. B. C. D.
1
6.
A transistor transistor can be checked using a(n) a(n) ________. A.
curve tracer
B.
digital meter
C.
ohmmeter
2 3 4
Answer: Option C
D. Any of the above above Answer: Option D
3.
Which of of the followi following ng equipment can check check the the condition of a transistor?
7.
What range range of resistor values would you get when checking a transistor for forward- and reversereversebiased conditions by an ohmmeter?
11. An example of a pnp silicon transistor is a 2N4123.
, exceeding 100 k
A.
True
Exceeding 100 k
, 100
B.
False
C.
Exce Excee eding ding 100 k
, excee ceeding ding 100 k
D.
100
, 100
A.
100
B.
to a few k
to a few k
Answer: Option B
to a few k
to a few k
Answer: Option A
8.
Calculate minority current I CO if IC = 20.002 mA and IC majority = 20 mA. A.
20
B.
0.002
A A
12. Which of the following is (are) the terminal(s) termin al(s) of a transistor? A.
Emitter
B.
Base
C.
Collector
D. All of the above above Answer: Option D
C.
2 nA 13. Use this table of collector collector characteristics to
D.
2
A
calculate
ac at
VCE = 15 V and I B = 30
A.
Answer: Option D
9.
What is (are) the component(s) component(s) of electrical electrical characteristics characteristics on the specification sheets? A.
On
B.
Off
C.
Small-signal characteristics characteristics
D. All of the above above Answer: Option D
10. In which region are both both the collector-base collector-base and base-emitter junctions forward-biased? A. Active
A.
100
B.
106
C.
50
D.
400
Answer: Option A
B.
Cutoff
C.
Saturation
A.
Common-base
D. All of the above above
B.
Common-emitter
Answer: Option C
14. Which of the followi following ng configurations can a transistor set up?
C.
18.
Common-collector
D. All of the above above Answer: Option D
15. What does a reading of a large or small resistance resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter? A.
Faulty device
A.
100
B.
Good device
B.
116
C.
Bad ohmmeter
C.
50
D.
None of the above
D.
110
Answer: Option D
Answer: Option A
16.
Determine the value of
when
19. Which of the followi following ng can be obtained from the last scale factor of a curve tracer?
= 100.
A.
1.01
A.
B.
101
B.
dc
C.
0.99
C.
ac
D.
Cannot be solved solved with the th e information provided
Answer: Option C
D.
hFE
ac
Answer: Option D
Calculate 17. Transistors are are ________-terminal devices. devices. A.
2
B.
3
C.
4
D.
5
Answer: Option B
Calculate
dc at
VCE = 15 V and IB = 30
A.
ac for I C =
15 mA and V CE = 5 V.
Answer: Option A
20.
23. What are the ranges of the ac input and output resistance for a common-base configuration? A.
10
B.
50 k
C.
10
D.
None of the above
–100 –1 M
, 50 k
–1 M
, 10
–100
–100 k
, 50
–1 k
Answer: Option A
24. What is the most frequently frequently encountered transistor configuration? A.
200
A.
Common-base
B.
180
B.
Common-collector
C.
220
C.
Common-emitter
D.
None of the above
D.
Emitter-collector
Answer: Option A
21.
dc =
________
A.
IB / I E
B.
IC / I E
C.
IC / I B
D.
None of the above
Answer: Option C
25.
dc for
this s et of collector characteristics is within
________ percent of
Answer: Option C
22. How many carriers carriers participate in the injection process of a unipolar device?
A.
2
A.
1
B.
5
B.
2
C.
7
C.
0
D.
10
D.
3
Answer: Option D
ac.
26. Which of the following following regions is (are) part of the output characteristics of a transistor?
30. For a properly biased biased pnp transistor, let I C = 10 mA and IE = 10.2 mA. What is the level of I B?
A. Active
A.
0.2 A
B.
Cutoff
B.
200 mA
C.
Saturation
C.
200
D. All of the above above
D.
20.2 mA
Answer: Option D
27. How many individual individual pnp silicon transistors can be housed in a 14 -pin plastic dual-in-line package?
A
Answer: Option C
31. What is (are) the component(s) of most specification specification sheets provided by the manufacturer?
A.
4
A.
Maximum ratings
B.
7
B.
Thermal characteristics
C.
10
C.
Electrical characteristics
D.
14
D. All of the above above
Answer: Option A
28. In what decade was was the first transistor transistor created? created? A.
1930s
B.
1940s
C.
1950s
D.
1960s
Answer: Option B
29. Most specification specification sheets are broken down into ________. A.
maximum ratings
B.
thermal characteri ch aracteristics stics
C.
electrical characteristics
D. All of the above above Answer: Option D
Answer: Option D
32.
What is
dc equal
to?
A.
IB / I E
B.
IC / I E
C.
IC / I B
D.
None of the above
Answer: Option C
33. List the types of bipolar junction transistors. transistors. A. ppn, npn B. pnp, npn C.
npp, ppn
D.
nnp, pnp
Answer: Option B
34. What is the ratio of the total width width to that of the center layer for a transistor?
D.
None of the above
A.
1:15
B.
1:150
C.
15:1
A.
hib
D.
150:1
B.
hfb
C.
hrb
D.
hob
Answer: Option C
3.
Answer: Option D
35. Which component of the collector collector current current IC is called the leakage current? A.
Majority
B.
Independent
C.
Minority
D.
None of the above
Which of the h-parameters h-parameters corresponds to r e in a common-base configuration?
Answer: Option A
4. Refer to this figure. Find the value of I E.
Answer: Option C
BJT AMPLIFIERS 1.
The current gain for for the Darlington Darlington connection is ________. A.
B.
2.
C.
A.
2 mA
D.
B.
4 mA
Answer: Option B
C.
5 mA
Which of the followi following ng configurations configurations has the the lowest lowest output impedance?
D.
6 mA
A.
Fixed-bias
B.
Voltage-divider
C.
Emitter-follower
Answer: Option D
5.
Which of the followi following ng is referred referred to as the reverse reverse transfer voltage ratio? A.
hi
B.
hr 8.
C.
hf
D.
For a common-emitter amplifier, amplifier, the purpose of swamping is A.
to minimize gain.
B.
to reduce the effects of r'e
C.
to maximize gain.
D.
no purpose.
ho
Answer: Option B
6.
Which of the followi following ng conditions must be met to allow the use of the approximate approach in a voltage-divider voltage-divider b ias configuration? A.
r e > 10R2
B.
RE > 10R2
C.
Answer: Option B
9.
What is the typical typical value value of the current gain of a common-base configuration? A.
Less than 1
B.
Between 1 and 50
C.
Between 100 and 200
D.
Undefined
RE < 10R2
D.
r e < 10R2
Answer: Option D
7. Refer to this figure. Determine the value of A v.
Answer: Option A
10. What is the most important r parameter for amplifier amplifier analysis? A.
r b′
B.
r c′
C.
r e′
Answer: Option C
11. An emitter-follower emitter-follower is also known as a A.
common-emitter amplifier.
A.
49.6
B.
common-base amp lifier. lifier.
B.
5
C.
common-collector common-collector amplifier.
C.
100
D.
Darlington Darlington pair.
D.
595
Answer: Option C
Answer: Option B
12. The ________ model fails fails to account for the output impedance level of the device and the feedback effect from output to input. A.
hybrid equivalent
B.
r e
D.
emitter-follower
Answer: Option C
15. What is the voltage voltage gain of a feedback pair connection? A.
1
C. B. –1 D.
Thevenin
Answer: Option B
13. Refer to this figure. Calculate the value of V B.
C.
100
D. –100 Answer: Option A
16. A common-emitter amplifier amplifier has ________ voltage gain, ________ current gain, ________ p ower ower gain, and ________ input impedance. A.
high, low, high, low
B.
high, high, high, low
C.
high, high, high, high
D.
low, low, low, high
Answer: Option B
17. What is the range of the input impedance of a common-base configuration?
A.
5V
B.
3.7 V
A. A few ohms to a maximum of 50
C.
20 V
B.
1k
D.
3V
C.
100 k
D.
1M
Answer: Option B
14. You have a need to apply an amplifier with a very high power gain. Which of the following would you choose? A.
common-collector
B.
common-base
C.
common-emitter
to 5 k to 500 k to 2 M
Answer: Option A
18. The advantage that a Sziklai pair has over over a Darlington Darlington pair is A.
higher current gain.
B.
less input voltage is needed to tu rn it on.
C.
higher input impedance.
B.
3.77 k
D.
higher voltage gain.
C.
378
D.
2.25 k
Answer: Option B
19. What is the typical range range of the output impedance of a common-emitte common -emitterr configuration? A.
10
to 100
B.
1k
to 5 k
C.
40 k
D.
500 k
22. What is the range of the current gain for BJT transistor amp lifiers? lifiers? A.
less than 1
to 50 k
B.
1 to 100
to 1 k
C.
above 100
Answer: Option C
20. What is the unit of the parameter ho? A.
Answer: Option B
D. All of the above above Answer: Option D
Volt 23. What does the negative sign in the voltage voltage gain of the common-emitter fixed-bias configuration indicate?
B.
Ohm
C.
Siemen
A.
The output and input voltages are 180º out of phase.
D.
No unit
B.
Gain is smaller than 1.
C.
Gain is larger than 1.
D.
None of the above
Answer: Option C
21. Refer to this figure. Calculate the value of R in(tot).
Answer: Option A
24. For the common-emitter fixed-bias fixed-bias configuration, configuration, there is a ________ phase sh ift between between the input and output signals. A.
0º
B.
45º
C.
90º
D.
180º
Answer: Option D A.
37.7 k
25. Which one of the following following configurations has the lowest input impedance? A.
Fixed-bias
B.
Common-base
C.
Emitter-follower
D.
Voltage-divider?
Answer: Option B
26. Which of the following following represent(s) the advantage(s) of the system approach over the r-model approach? A.
Thevenin's theorem can be used.
B.
The effect of changing the load can b e determined by a simple equation.
C.
There is no need to go back to the ac equivalent model and analyze the entire network.
D. All of the above above Answer: Option D
27. The differential differential amplifier amplifier has A.
D.
high, high
Answer: Option C
29. The differential differential amplifier produces produces outputs that are A.
common mode.
B.
in-phase with the input voltages.
C.
the sum of the two input voltages. voltages.
D.
the difference of the two input voltages.
Answer: Option D
30. The ________ model suffers suffers from being limited to a particular set of operating conditions if it is to be considered accurate. A.
hybrid equivalent
B.
r e
C. D.
Thevenin
Answer: Option A
one input and one output. 31. Under which of the following following condition(s) is the
B. C. D.
two inputs and two outputs.
?
A.
r o
10RC
B.
RB
10r e
C.
r o
D.
None of the above
two inputs and one output. one input and two outputs.
Answer: Option C
28. The emitter-follower emitter-follower configuration configuration has a ________ impedance at the input and a ________ impedance at the output. A.
current gain
10RC and RB
10r e
Answer: Option C
low, low
B.
low, high
C.
high, low
32. The ________ configuration configuration is frequently used for impedance matching. A.
fixed-bias
B.
voltage-divider voltage-divider bias
C.
emitter-follower
D.
collector feedback
35. Refer to this figure. Determine the value of V C.
Answer: Option C
33. Refer to this figure. You You notice while servicing servicing this amplifier that the output signal at V out is reduced from normal. The problem could be caused by
A. B. C.
A.
20 V
B.
10 V
C.
5V
D.
0V
an open C3. an open C2. an open base-emitter b ase-emitter of Q2. Answer: Option C
D.
a shorted C2.
Answer: Option B
34. When the bypass capacitor is removed removed from a common-emitter amplifier, amplifier, the voltage gain A. B. C.
36. In a common-base amplifier, amplifier, the input signal is connected to the A.
base.
B.
collector.
C.
emitter.
D.
output.
increases. decreases. has very little effect. Answer: Option C
Answer: Option B
37. Which of the following following is (are) true to achieve a good overall voltage gain for the circuit? A.
The effect of R s and RL must be considered as a product.
B.
The effect of R s and RL must be considered as a product and evaluated evaluated individually.
C.
The effect of R s and RL must be evaluated individually.
D.
None of the above
40.
Answer: Option B
38. To analyze the common-emitter amplifier amplifier,, what must be done to determine the d c equivalent equivalent circuit? A.
leave circuit unchanged
B.
replace coupling and bypass capacitors with opens
C.
replace coupling and bypass b ypass capacitors with shorts
D.
replace VCC with ground
A.
416
B.
5k
C.
50 k
D.
500
Answer: Option B
39. For the common-emitter amplifier amplifier ac ac equivalent circuit, all capacitors are A.
effectively shorts. Answer: Option A
B.
effectively open circuits.
C.
not connected to g round.
D.
connected to ground.
Answer: Option A
Refer to this figure. If an emitter bypass capacitor was installed, determine the value of R in(base).
41. Under which of the following following conditions is the output impedance of the n etwork etwork approximately equal to RC for a comm on-emitter fixed-bias configuration? configuration? A.
r o
B.
r o < 10RC
C.
r o < r o
D.
r o > r o
10RC
Answer: Option A
42. Which of the following following gains g ains is less than 1 for a common-base configuration? A. Ai B. Av C. Ap
D.
None of the above
C.
r e
Answer: Option A D.
43. Which of the following following define(s) the conversion efficiency? A. Ac power to the load/ac input power power B. Ac power to the load/dc power supplied C.
Ib
Answer: Option C
47. Which of the followi following ng is (are) true regarding regarding the input impedance for frequencies in the midrange 100 kHz of a BJT transistor amplifier? A.
The input impedance is purely resistive. resistive.
B.
It varies from a few ohms to megohms.
Dc output power/ac input power
D. All of the above above Answer: Option B
44. The dc emitter current of a transistor is 8 mA. What is the value of r e? A.
320
B.
13.3 k
C.
3.125
D.
5.75
C.
An ohmmeter cannot be used used to measure the small-signal ac input impedance.
D. All of the above above Answer: Option D
48. For the collector collector dc feedback configuration, there is a ________ phase shift between the input and output signals. A.
0º
B.
45º
C.
90º
D.
180º
Answer: Option C
45. Which of the following following should be done to obtain obtain the ac equivalent of a network? A.
Set all dc sources to zero
B.
Replace all capacitors by a sh ort-circuit equivalent.
C.
Remove all elements bypassed by the shortcircuit equivalent.
D. All of the above above Answer: Option D
46. In an unbypassed emitter bias configuration configuration hie replaces ________ in the r e model. A. B.
r e
Answer: Option D
49. A common-collector common-collector amplifier amplifier has ________ input resistance, ________ current gain, and ________ voltage gain. A.
high, high, low
B.
high, low, low
C.
high, low, high
Answer: Option A
50. The total gain of a multistage mult istage amplifier is the ________. A.
sum of individual voltage gains
B.
sum of dB voltage gains
Answer: Option B
51. Which of the following following configurations configurations has an output impedance Zo equal to RC? A.
Fixed-bias Fixed-bias common-emitter
B.
Common-emitter voltage-divider voltage-divider with bypass capacitor
C.
Common-emitter voltage-divider without bypass capacitor
B.
to reduce noise.
C.
to despike the supply voltage.
D.
to maximize amplifier gain.
Answer: Option D
54. For BJT amplifiers, amplifiers, the ________ gain typically ranges from a level just less than 1 to a level that may exceed 1000. A.
voltage
B.
current
C.
impedance
D. All of the above above Answer: Option D
D. All of the above above
52. Refer to this figure. Find the value of R in(base). Answer: Option B
55. The loaded voltage gain of an amplifier is always more than the no-load level. A.
True
B.
False
Answer: Option B
56. Which of the following following configurations has a voltage gain of –RC /r e?
A.
420
B.
50 k
C.
940
D.
A.
Fixed-bias Fixed-bias common-emitter
B.
Common-emitter voltage-divider voltage-divider with bypass capacitor
C.
Fixed-bias Fixed-bias common-emitter comm on-emitter and voltagedivider with bypass capacitor
D.
Common-emitter voltage-divider without bypass capacitor
100.8 Answer: Option C
Answer: Option B
53. For a common-emitter amplifier, amplifier, the purpose of the emitter bypass capacitor is A.
no purpose, since it is shorted out by RE.
57. An emitter-follower emitter-follower amplifier amplifier has an input impedance of 107 k . The The input input signal signal is 12 mV. mV. The The approximate output voltage is (comm on-collector) A.
8.92 V
B.
112 mV
C.
12 mV
D.
8.9 mV
Answer: Option C
58. Which of the following following is (are) true regarding the output impedance for frequencies in the midrange 100 kHz of a BJT transistor amplifier? A.
60. What is the limit of the efficiency efficiency defined defined by = P o / Pi? A.
Greater than 1
B.
Less than 1
C. Always Always 1 D.
None of the above
Answer: Option B
The output impedance is purely resistive. 61. What is r e equal to in terms of h parameters?
B.
C.
It varies from a few ohms to more than 2 M . An ohmmeter cannot be used to measure the small-signal ac output impedance.
D. All of the above above
A.
hre / hoe
B.
(hre + 1) / h oe
C.
hie – (hre / hoe)(1 + h fe)
D.
hfe
E.
none of the above
Answer: Option D
59. Refer to this figure. The The output signal from the first stage of this amplifier is 0 V. The trouble could be caused by
Answer: Option A
62. What is the controlling controlling current in a common-base configuration? A.
Ie
B.
Ic
C.
Ib
D.
None of the above
Answer: Option A A.
an open C4.
B.
an open C2.
A.
Small-signal
C.
an open base-emitter b ase-emitter of Q1.
B.
Large-signal
D.
a shorted C4.
C.
Small- or large-signal
D.
None of the above
Answer: Option C
63. Which of the following following techniques can be used in the sinusoidal ac analysis of transistor networks?
Answer: Option C
64. The input impedance impedan ce of a BJT amplifier is purely ________ in nature and can vary vary from from a few ________ to ________.
C.
398
D.
600
A.
resistive, ohms, megohms
B.
capacitive, microfarads, farads
C.
inductive, millihenrys, henrys
A.
multiplication, multiplication, decreased d ecreased
D.
None of the above
B.
multiplication, multiplication, increased increased
C.
division, division, decreased
Answer: Option D
67. A Darlington pair pair provides beta ________ for for ________ input resistance. resistance.
Answer: Option A
65. The ________ the source source resistance resistance and/or ________ the load resistance, resistance, the less the overall overall gain of an amplifier. amplifier. A.
smaller, smaller
B.
smaller, larger
C.
larger, smaller
D.
Answer: Option B
68. A Darlington pair pair amplifier amplifier has A.
high input impedance and high voltage gain.
B.
low input impedance and low voltage gain.
C.
a voltage gain of about 1 and a low input impedance.
D.
a low voltage gain and a high input impedance.
larger, larger
Answer: Option C
Answer: Option D
66. Refer to this figure. If an emitter bypass capacitor was installed, what would the n ew Av be?
FET DEVICES 1.
Which of of the follow following ing ratings ratings appear(s) appear(s) in the specification specification sheet for an FET? A.
Voltages between specific terminals
B.
Current levels
C.
Power dissipation
D. All of the above above Answer: Option D
2. A.
4.96
B.
125
What is the level of drain current ID for gate-tosource voltages VGS less than (more negative than) the pinch-off level? A.
zero amperes
B.
IDSS
C.
Negative value
D.
Undefined
Answer: Option A
3.
What is is the level of I G in an FET? FET? A.
Zero amperes
A.
B.
Equal to ID
B. –25 Vdc, 10 mAdc
C.
Depends on VDS
C. –6 Vdc, –1.0 nAdc
D.
Undefined
D.
Answer: Option A
4.
What is the range of of an FET's FET's input impedance? A. B. C. D.
10 1k
7.
to 1 k
50 k
to 100 k
1M
to several hundred M
8.
Power should always be off when network changes are made. Always touch touch ground before handling the device.
No bias
B.
VDS > 0 V
C.
VDS = VP
D.
None of the above
Answer: Option D
Refer to this portion portion of of a specification specification sheet. Determine the values of reverse-gate-source voltage and gate current if the FET was forced to accept it.
What is the ratio of ID / I DSS for V GS = 0.5 V P? A.
0.25
B.
0.5
C.
1
D.
0
Answer: Option A
D. All of the above above
6.
A.
Answer: Option A
A. Always pick up the transistor by the casing. casing.
C.
At which which of the following following condition(s) condition(s) is the depletion depletion region uniform?
to 10 k
Which of the following following applies to a safe safe MOSFET MOSFET handling?
B.
None of the above
Answer: Option B
Answer: Option D
5.
25 Vdc, –200 nAdc
9.
Referring Referring to this transfer curve, determine determine I D at VGS = 2 V.
12. The BJT is a ________ device. The FET is a ________ device. A.
bipolar, bipolar
B.
bipolar, unipolar
C.
unipolar, bipolar
D.
unipolar, unipolar
Answer: Option B
A.
0.444 mA
B.
1.333 mA
C.
0.111 mA
D.
4.444 mA
13. Referring Referring to this transfer curve. Calculate (using (using Shockley's equation) VGS at ID = 4mA.
Answer: Option A
10. Which of the following following controls the level of ID? A.
VGS
B.
VDS
C.
IG
D.
VDG
A.
2.54 V
Answer: Option A B. –2.54 V
11. It is the insulating layer layer of ________ in the MOSFET construction that accounts for the very desirable high input impedance of the device. A.
SiO
B.
GaAs
C.
SiO2
D.
HCl
C. –12 V D.
Undefined
Answer: Option B
14. The drain current will will always always be one-fourth one- fourth of IDSS as long as the gate-to-source voltage is ________ the pinch-off value. A.
one-fourth
B.
one-half
Answer: Option C
C.
three-fourths
D.
None of the above
Answer: Option B
15. The transfer curve curve is not defined by Shockley's equation for the ________. A.
JFET
B.
depletion-type MOSFET
C.
enhancement-type MOSFET
D.
BJT
Answer: Option C
16. What is the purpose of adding two two Zener diodes to the MOSFET in this figure?
A.
1.66 V
B. –1.66 V C.
0.66 V
D. –0.66 V Answer: Option A
A. B. C. D.
To reduce the input impedance
18. The region region to the left of the pinch-off pinch-off locus is referred to as the ________ region. A.
saturation
B.
cutoff
C.
ohmic
To protect the MOSFET for both p olarities olarities To increase the input impedance None of the above D. All of the above above
Answer: Option B Answer: Option C
17. Referring Referring to the following transfer curve, determine determine the level of V GS when the drain current is 20 mA.
19. Refer to the following following curves. Calculate ID at VGS = 1 V.
Answer: Option C
21. The three terminals terminals of the JFET are the ________, ________, and ________. A.
gate, collector, emitter
B.
base, collector, emitter
C.
gate, drain, source
D.
gate, drain, emitter
Answer: Option C
22. Which of the following is (are) the terminal(s) termin al(s) of a field-effect transistor (FET). (FET). A.
Drain
B.
Gate
C.
Source
D. All of the above above Answer: Option D
A.
8.167 mA
B.
4.167 mA
C.
6.167 mA
D.
0.616 mA
Answer: Option B
20. Which of the following following transistor(s) has (have) (have) depletion and enhancement types?
23. A BJT is a ________-controlled device. device. The JFET is is a ________ - cont rolled rolled device. A.
voltage, voltage
B.
voltage, current
C.
current, voltage
D.
current, current
Answer: Option C
24. How many terminals terminals can a MOSFET have?
A.
BJT
A.
2
B.
JFET
B.
3
C.
MOSFET
C.
4
D.
None of the above
D.
3 or 4
Answer: Option D
A.
No direct electrical connection between the gate terminal and the channel
B.
Desirable Desirable high input impedance
C.
Uses metal for the gate, drain, and source connections
25. Refer to the following following figure. Calculate VGS at ID = 8 –2 mA for k = 0.278 × 10 –2 A/V2.
28.
D. All of the above above Answer: Option D A.
3.70 V
B.
5.36 V
C.
7.36 V
D.
2.36 V
29. At which of the following following is the level of V DS equal to the pinch-off voltage? A.
When ID becomes equal to I DSS
B.
When VGS is zero volts
C.
IG is zero
Answer: Option A D. All of the above above
26. The level of VGS that results in I D = 0 mA is d efined by VGS = ________. A.
Answer: Option D
VGS(off)
B.
VP
C.
VDS
D.
None of the above
30. Which of the following following represent(s) the cutoff region region for an FET? A.
ID = 0 mA
B.
VGS = VP
C.
IG = 0
Answer: Option B D. All of the above above
27. Which of the following following FETs has the lowest input impedance? A.
Answer: Option D
JFET
B.
MOSFET depletion-type
C.
MOSFET enhancement-type enh ancement-type
D.
None of the above
31. Which of the following following is (are) the advantage(s) of VMOS over MOSFETs? A.
Reduced channel resistance
B.
Higher current and power ratings
C.
Faster switching time
Answer: Option A D. All of the above above
Which of the following following applies to MOSFETs? MOSFETs?
Answer: Option D
32. Hand-held instruments are are available to measure measure ________ for the BJT. BJT. A.
35. Which of the following following is (are) not an FET? A.
n-channel
dc B. p-channel
B.
IDSS C. p-n channel
C.
VP D.
D. All of the above above
n-channel and p-channel
Answer: Option C
Answer: Option A
FET AMPLIFIERS 33. Which of the following following input impedances is not valid valid for a JFET? A.
10 10
B.
10 9
C.
10 8
D.
10 11
1.
Answer: Option C
34. Refer to the following characteristic characteristic curve. Calculate the resistance of the FET at V GS = –0.25 V if r o= 10 k .
A common-gate common-gate amplifier is similar in configuration configuration to which BJT B JT amplifier? amplifier? A.
common-emitter
B.
common-collector
C.
common-base
D.
emitter-follower
Answer: Option C
2.
The theoretical efficiency efficiency of a class D amplifier is A.
75%.
B.
85%.
C.
90%.
D.
100%.
Answer: Option D
3. A. B. C. D.
1.1378 k
A common-source amplifier amplifier is similar in configuration to which BJT amplifier? amplifier? A.
common-base
B.
common-collector
C.
common-emitter
D.
emitter-follower
113.78 11.378 11.378 k
Answer: Option D
Answer: Option C
4.
Refer to this figure. If R 6 opened, the signal at the drain of Q 1 would 6.
A.
current
B.
voltage
Answer: Option A
7.
A.
increase.
B.
decrease.
C.
remain the same.
D.
distort.
Answer: Option C
Referring Referring to this figure, calculate A v if r d = 19 k
.
A. –2.85
5. Refer to this figure. Find Find the value value of VD.
B. –3.26 C. –2.95 D. –3.21 Answer: Option C
8.
A.
A common-drain common-drain amplifier amplifier is similar in configuration configuration to which BJT B JT amplifier? amplifier? A.
common-emitter
B.
common-collector
C.
common-base
D.
common-gate
20 V
B.
11 V
C.
10 V
Answer: Option B
Referring Referring to this figure, calculate A v for yos = 58 D.
9V
Answer: Option D
A BJT is a ________-controlled ________-controlled device. device.
S.
9.
D.
0 V p-p.
Answer: Option A
11. Use the following following equation to calculate calculate gm for a JFET having I DSS = 10 mA, V P = –5 V, and V GSQ = – 2.5 V.
A. –7.29 B. –7.50 C. –8.05
A.
2 mS
B.
3 mS
C.
4 mS
D.
5 mS
Answer: Option A
12. For what what value of ID is gm equal to 0.5 g m0? A.
0 mA
B.
0.25 IDSS
C.
0.5 IDSS
D.
IDSS
D. –8.55 Answer: Option A
0. Refer to this figure. If Vin = 1 V p -p, the output voltage voltage Vout would be
Answer: Option B
13. Refer to this figure. If V in = 20 mV p-p what is the output voltage?
A.
undistorted.
B.
clipped on the negative peaks.
C.
clipped on the positive peaks.
A.
176 mV p-p
B.
88 mV p-p
C.
48 mV p-p
D.
24 mV p-p
15.
Answer: Option A
14. Referring Referring to the following figure, calculate gm for VGSQ = –1.25 V.
A.
2.2 k
B.
2.42 k
C.
2.62 k
D.
2.82 k
Answer: Option D A.
2 mS
B.
2.5 mS
A.
from the dc biasing arrangement
C.
2.75 mS
B.
from the specification sheet
D.
3.25 mS
C.
from the ch aracteristics aracteristics
Answer: Option C
Referring Referring to this figure, calculate the value of R D if the ac gain is 10. Assume VGSQ = ¼Vp.
16. Where do you get the level of gm and r d for an FET transistor?
D. All of the above above Answer: Option D
17. The class D amplifier amplifier uses what type of transistors? transistors? A.
JFETs
B.
BJTs
C.
MOSFETs
D.
any of the above
Answer: Option C
18. What is (are) (are) the function(s) of the coupling coupling capacitors C1 and C2 in an FET circuit? A.
to create an open circuit for dc analysis analysis
B.
to isolate the dc biasing arrangement from the applied signal and load
C.
to create a short-circuit equivalent for ac analysis
D. All of the above above Answer: Option D
19. An FET is is a ________-controlled device. device. A. B.
A.
increase.
B.
decrease.
C.
remain the same.
D.
distort.
current voltage Answer: Option C
Answer: Option B
23. Referring Referring to th is figure, find Z o if yos = 20
S.
20. What is the the input resistance (Rin(source)) of a commongate amplifi amp lifier? er? A.
Rs
B. C.
1 / gm
D.
none of the above
Answer: Option C
21. There is a ________º phase inversion inversion between between gate and source in a source follower. follower. A.
0
B.
90
C.
180
D.
none of the above
Answer: Option A
22. Refer to this figure. figure. If C4 opened, th e signal voltage at the drain of Q 1 would
A.
1.85 k
B.
1.92 k
C.
2.05 k
D.
2.15 k
Answer: Option B
24. Which of the following following is a required condition to simplify the equations for Z o and Av for the self-bias configuration?
