Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
The tunnel diode region of operation between VP and VV is called the ________.
1)
A)
negative resistance region
B)
negative current region
C)
constant resistance region
D)
constant current region
Answer:
A
A)
B)
C)
D)
2)
In the Schottky diode, the injected carriers have a very high kinetic energy level compared to the
electrons of the metal; as a result the device is called a(n) ________ diode.
2)
A)
energy
B)
junction
C)
hot–carrier
D)
None of the above
Answer:
C
A)
B)
C)
D)
3)
When frequency increases, the Q of a varactor diode ________ .
3)
A)
increases
B)
only changes with reverse current
C)
decreases
D)
only changes with reverse voltage
Answer:
C
A)
B)
C)
D)
4)
Hot–carrier refers to ________ diodes.
4)
A)
Schottky
B)
tunnel
C)
photoconductive
D)
pin
Answer:
A
A)
B)
C)
D)
1
5)
This is the symbol for a(n) ________.
5)
A)
tunnel diode
B)
thermistor
C)
Schottky diode
D)
varactor diode
Answer:
D
A)
B)
C)
D)
6)
The most unique feature of the characteristics of the tunnel diode is ________.
6)
A)
negative resistance region
B)
very low positive resistance region
C)
almost zero breakdown voltage implying almost non–existent depletion region
D)
very high positive resistance region
Answer:
A
A)
B)
C)
D)
7)
The capacitance of a varactor diode depends on ________
7)
A)
the permittivity of the semiconductor material
B)
area of the depletion region
C)
width of the depletion region
D)
All of the above
Answer:
D
A)
B)
C)
D)
8)
The most widely used material for solar cells are ________.
8)
A)
gallium arsenide and cadmium sulfide
B)
selenium and silicon
C)
indium arsenide and gold
D)
None of the above
Answer:
B
A)
B)
C)
D)
2
9)
LCDs are limited to a temperature range of ________.
9)
A)
0 to 60 degrees C
B)
0 to 10 degrees C
C)
30 to 100 degrees C
D)
0 to 100 degrees C
Answer:
A
A)
B)
C)
D)
10)
The photodiode characteristics show equal spacing between the diode current curves for an equal
increase in photon energy. So a graph of radiant flux versus diode current is a(n) ________
relationship.
10)
A)
linear
B)
square
C)
parabolic
D)
exponential
Answer:
A
A)
B)
C)
D)
11)
A typical solar cell has an efficiency of approximately ________.
11)
A)
75 – 80%
B)
10 – 40%
C)
25 – 30%
D)
1 – 3%
Answer:
B
A)
B)
C)
D)
12)
LCDs have power dissipation on the order of ________.
12)
A)
micro–Watts
B)
milli–Watts
C)
Watts
D)
None of the above
Answer:
A
A)
B)
C)
D)
13)
Optoelectronic devices are generally classified as ________.
13)
A)
optical couplers or optical isolators
B)
optical emitters or optical detectors
C)
optically discrete or optically integrated
D)
optical diodes or optical transistors
Answer:
B
A)
B)
C)
D)
3
14)
Minimum solar cell efficiency is about ________.
14)
A)
1%
B)
70%
C)
10%
D)
30%
Answer:
C
A)
B)
C)
D)
15)
A varactor with a high capacitance ratio (CR) rating is well–suited for ________.
15)
A)
crystal–controlled oscillator applications
B)
fine–tuning applications
C)
coarse–tuning applications
D)
extremely high–Q applications
Answer:
C
A)
B)
C)
D)
16)
LCDs degrade ________.
16)
A)
in a dry place
B)
quickly
C)
chemically
D)
All of the above
Answer:
C
A)
B)
C)
D)
17)
Optoelectronic devices are generally classified as being either ________.
17)
A)
discrete or integrated
B)
couplers or isolators
C)
emitters or detectors
D)
input or output devices
Answer:
C
A)
B)
C)
D)
18)
Field effect, or twisted neumatic, LCDs require a(n) ________ to be applied in order for the light to
be seen by the viewer.
18)
A)
constant voltage
B)
alternating voltage
C)
constant current
D)
alternating current
Answer:
A
A)
B)
C)
D)
4
19)
An LCD has power dissipation on the order of ________.
19)
A)
milli–watts
B)
micro–watts
C)
watts
D)
None of the above
Answer:
B
A)
B)
C)
D)
20)
The varactor acts as a ________.
20)
A)
voltage–controlled capacitance when reverse biased
B)
voltage–controlled capacitance when forward biased
C)
current–controlled capacitance when reverse biased
D)
current–controlled capacitance when forward biased
Answer:
A
A)
B)
C)
D)
21)
This is the symbol for a(n) ________.
21)
A)
photodiode
B)
thermistor
C)
light–emitting diode
D)
varicap
Answer:
A
A)
B)
C)
D)
22)
As the reverse bias potential across a varactor diode increases, the transition capacitance ________.
22)
A)
remains constant
B)
increases linearly
C)
increases exponentially
D)
decreases
Answer:
D
A)
B)
C)
D)
5
23)
This is the symbol for a(n) ________.
23)
A)
tunnel diode
B)
thermistor
C)
varicap diode
D)
Schottky diode
Answer:
A
A)
B)
C)
D)
24)
The typical infrared–emitting diode has a radiant flux versus dc current curve that is ________.
24)
A)
an exponential relationship
B)
an almost linear relationship
C)
a square relationship
D)
None of the above
Answer:
B
A)
B)
C)
D)
25)
The Schottky diode is used for ________.
25)
A)
low voltage/high current power supplies
B)
very high frequency applications
C)
low noise applications
D)
All of the above
Answer:
D
A)
B)
C)
D)
26)
A thermistor is a temperature sensitive semiconductor resistor that has ________.
26)
A)
negative temperature coefficient
B)
negative temperature coefficient at low temperature, positive temperature coefficient at high
temperature
C)
positive temperature coefficient
D)
a temperature coefficient that may be either positive or negative
Answer:
C
A)
B)
C)
D)
6
27)
This is the symbol for a(n) ________.
27)
A)
photoresistor
B)
thermistor
C)
variac
D)
optoresistor
Answer:
B
A)
B)
C)
D)
28)
The tunnel diode is a ________.
28)
A)
lightly doped diode that greatly increases the depletion region
B)
heavily doped diode that greatly reduces the depletion region
C)
lightly doped diode that greatly reduces the depletion region
D)
heavily doped diode that greatly increases the depletion region
Answer:
B
A)
B)
C)
D)
29)
A thermistor is a temperature–sensitive semiconductor resistor that has ________ p–n junctions.
29)
A)
no
B)
one
C)
two
D)
three
Answer:
A
A)
B)
C)
D)
30)
The resistance of the photoconductive device varies directly with the intensity of the incident light.
The relationship between the resistance and the light intensity is a(n) ________ relationship.
30)
A)
square
B)
linear
C)
exponential
D)
parabolic
Answer:
B
A)
B)
C)
D)
31)
In a tank circuit employing a varactor diode, the coupling capacitor ________ .
31)
A)
has no application, there is no coupling cap
B)
couples the signal to the amplifier
C)
has no effect on C‘T
D)
isolates the bias voltage from the inductor
Answer:
D
A)
B)
C)
D)
7
32)
Varactor diodes are also known as ________ diodes.
32)
A)
XCvar
B)
varigen
C)
reactance
D)
varicap
Answer:
D
A)
B)
C)
D)
33)
This is the symbol for a(n) ________.
33)
A)
photodiode
B)
tunnel diode
C)
Schottky diode
D)
varactor diode
Answer:
B
A)
B)
C)
D)
34)
This is the symbol for a(n) ________.
34)
A)
Schottky diode
B)
thermistor
C)
tunnel diode
D)
varactor diode
Answer:
A
A)
B)
C)
D)
35)
Tunnel diodes are often used as the active devices in ________.
35)
A)
negative current rectifiers
B)
constant resistance amplifier
C)
negative resistance oscillators
D)
negative resistance linear amplifiers
Answer:
C
A)
B)
C)
D)
8
36)
The capacitance of a varactor is ________.
36)
A)
directly proportional to the width of the depletion layer
B)
inversely proportional to the amount of diode reverse voltage
C)
inversely proportional to the permittivity of the semiconductor material
D)
None of the above
Answer:
B
A)
B)
C)
D)
37)
A typical four solar cell array can deliver ________ of power.
37)
A)
5.83 mW
B)
10.7 mW
C)
4.16 mW
D)
20 mW
Answer:
C
A)
B)
C)
D)
38)
LCDs require a(n) ________.
38)
A)
internal light source
B)
constant current
C)
constant voltage
D)
large heat sink
Answer:
A
A)
B)
C)
D)
9
Answer Key
Testname: C16
1)
A
2)
C
3)
C
4)
A
5)
D
6)
A
7)
D
8)
B
9)
A
10)
A
11)
B
12)
A
13)
B
14)
C
15)
C
16)
C
17)
C
18)
A
19)
B
20)
A
21)
A
22)
D
23)
A
24)
B
25)
D
26)
C
27)
B
28)
B
29)
A
30)
B
31)
D
32)
D
33)
B
34)
A
35)
C
36)
B
37)
C
38)
A