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terms ^^ > semicon & diodes > Flashcards

semicon & diodes Flashcards

1
Q

Intrinsic semiconductor material is characterized by a valence shell of how many electrons?
1
2
4
6

A

4

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2
Q

Ionization within a P-N junction causes a layer on each side of the barrier called the:
junction
depletion region
barrier voltage
forward voltage

A

depletion region

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3
Q

What is the most significant development in electronics since World War II?
the development of color TV
the development of the diode
the development of the transistor
the development of the TRIAC

A

the development of the transistor

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4
Q

What causes the depletion region?
doping
diffusion
barrier potential
ions

A

diffusion

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5
Q

What is an energy gap?
the space between two orbital shells
the energy equal to the energy acquired by an electron passing a 1 V electric field
the energy band in which electrons can move freely
an energy level at which an electron can exist

A

the space between two orbital shells

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6
Q

Silicon atoms combine into an orderly pattern called a:
covalent bond
crystal
semiconductor
valence orbit

A

crystal

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7
Q

In “n” type material, majority carriers would be:
holes
dopants
slower
electrons

A

electrons

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8
Q

Elements with 1, 2, or 3 valence electrons usually make excellent:
conductors
semiconductors
insulators
neutral

A

conductors

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9
Q

A commonly used pentavalent material is:
arsenic
boron
gallium
neon

A

arsenic

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10
Q

Which material may also be considered a semiconductor element?
carbon
ceramic
mica
argon

A

carbon

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11
Q

In “p” type material, minority carriers would be:
holes
dopants
slower
electrons

A

electrons

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12
Q

What can a semiconductor sense?
magnetism
temperature
pressure
all of the above

A

all of the above

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13
Q

When an electron jumps from the valence shell to the conduction band, it leaves a gap. What is this gap called?
energy gap
hole
electron-hole pair
recombination

A

hole

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14
Q

Forward bias of a silicon P-N junction will produce a barrier voltage of approximately how many volts?
0.2
0.3
0.7
0.8

A

0.7

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15
Q

Which semiconductor material is made from coal ash?
germanium
silicon
tin
carbon

A

germanium

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16
Q

When and who discovered that more than one transistor could be constructed on a single piece of semiconductor material:
1949, William Schockley
1955, Walter Bratten
1959, Robert Noyce
1960, John Bardeen

A

1959, Robert Noyce

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17
Q

When is a P-N junction formed?
in a depletion region
in a large reverse biased region
the point at which two opposite doped materials come together
whenever there is a forward voltage drop

A

the point at which two opposite doped materials come together

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18
Q

A P-N junction mimics a closed switch when it:
has a low junction resistance
is reverse biased
cannot overcome its barrier voltage
has a wide depletion region

A

has a low junction resistance

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19
Q

Solid state devices were first manufactured during:
World War 2
1904
1907
1960

A

1960

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20
Q

Electron pair bonding occurs when atoms:
lack electrons
share holes
lack holes
share electrons

A

share electrons

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21
Q

How many valence electrons are in every semiconductor material?
1
2
3
4

A

4

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22
Q

What is a type of doping material?
extrinsic semiconductor material
pentavalent material
n-type semiconductor
majority carriers

A

pentavalent material

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23
Q

Minority carriers are many times activated by:
heat
pressure
dopants
forward bias

A

heat

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24
Q

What is the voltage across R1 if the P-N junction is made of silicon?

12 V
11.7 V
11.3 V
0 V

A

11.3 V

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25
Q

If conductance increases as temperature increases, this is known as a:
positive coefficient
negative current flow
negative coefficient
positive resistance

A

negative coefficient

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26
Q

Which of the following cannot actually move?
majority carriers
ions
holes
free electrons

A

ions

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27
Q

What electrical characteristic of intrinsic semiconductor material is controlled by the addition of impurities?
conductivity
resistance
power
all of the above

A

Conductivity

28
Q

What is a varistor?
a voltage-dependent resistor
a voltage-dependent diode
a current-dependent resistor
a current-dependent diode

A

a voltage-dependent resistor

29
Q

Which type of transformer is required to create a 180 degree input to a rectifier?
center-tapped secondary
step-down secondary
stepped-up secondary
split winding primary

A

center-tapped secondary

30
Q

What circuit activity may shift a characteristic curve so that diode operating points are different?
higher power (heat)
higher resistance
lower voltage
lower current

A

higher power (heat)

31
Q

The dc current through each diode in a bridge rectifier equals:
the load current
half the dc load current
twice the dc load current
one-fourth the dc load current

A

the load current

32
Q

When matching polarity connections have been made and the potential difference (PD) is above 0.7 V, the diode is considered to be:
not working
forward biased
reverse biased
an open switch

A

forward biased

33
Q

In a power supply diagram, which block indicates a smooth dc output?
transformer
filter
rectifier
regulator

A

regulator

34
Q

The characteristic curve for the complex model of a silicon diode shows that
the barrier potential is 0 V
the barrier potential stays fixed at 0.7 V
the barrier potential increases slightly with an increase in current
the barrier potential decreases slightly with an increase in current

A

the barrier potential increases slightly with an increase in current

35
Q

Since diodes are destroyed by excessive current, circuits must have:
higher voltage sources
current limiting resistors
more dopants
higher current sources

A

current limiting resistors

36
Q

A diode for which you can change the reverse bias, and thus vary the capacitance is called a
varactor diode
tunnel diode
zener diode
switching diode

A

varactor diode

37
Q

A filtered full-wave rectifier voltage has a smaller ripple than does a half-wave rectifier voltage for the same load resistance and capacitor values because:
there is a shorter time between peaks
there is a longer time between peaks
the larger the ripple, the better the filtering action
none of the above

A

there is a shorter time between peaks

38
Q

Testing a good diode with an ohmmeter should indicate
high resistance when forward or reverse biased
low resistance when forward or reverse biased
high resistance when reverse biased and low resistance when forward biased
high resistance when forward biased and low resistance when reverse biased

A

high resistance when reverse biased and low resistance when forward biased

39
Q

The peak inverse voltage (PIV) across a nonconducting diode in a bridge rectifier equals approximately:
half the peak secondary voltage
twice the peak secondary voltage
the peak value of the secondary voltage
four times the peak value of the secondary voltage

A

the peak value of the secondary voltage

40
Q

Electrons in the outermost orbit or shell of an atom are called
free electrons
negative ions
valence electrons
conduction band electrons

A

valence electrons

41
Q

Shunting the ac component away from the load is the task of a:
transformer
filter
regulator
rectifier

A

filter

42
Q

A pn junction allows current flow when
the p-type material is more positive than the n-type material
the n-type material is more positive than the p-type material
both the n-type and p-type materials have the same potential
there is no potential on the n-type or p-type materials

A

the p-type material is more positive than the n-type material

43
Q

When a diode is forward biased, the voltage across it
is directly proportional to the current
is inversely proportional to the current
is directly proportional to the source voltage
remains approximately the same

A

remains approximately the same

44
Q

Why is heat produced in a diode?
due to current passing through the diode
due to voltage across the diode
due to the power rating of the diode
due to the PN junction of the diode

A

due to current passing through the diode

45
Q

The arrow in the schematic symbol of a diode points to
the n-type material, which is called the anode
the n-type material, which is called the cathode
the p-type material, which is called the anode
the p-type material, which is called the cathode

A

the p-type material, which is called the anode

46
Q

The diode schematic arrow points to the:
trivalent-doped material
positive axial lead
anode lead
cathode lead

A

cathode lead

47
Q

When checking a diode, low resistance readings both ways indicate the diode is:
open
satisfactory
faulty
not the problem

A

faulty

48
Q

In a diode schematic, the anode is represented by a(n):
triangle
vertical line
zig-zag line
element indicator

A

triangle

49
Q

An IC regulator receives an overload; it will:
shut down
compensate for heat
provide more voltage
sample and adjust

A

shut down

50
Q

With full-wave rectification, current through the load resistor must be:
in opposite directions
to the external load
from the reverse biased diode
in the same direction

A

in the same direction

51
Q

A characteristic curve is the result of a current versus voltage plot of diode activity, which begins at the:
3rd quadrant
current plot
graph origin
voltage plot

A

graph origin

52
Q

Rectifier output polarity depends upon:
cycles of input
capacitor polarity
half or full wave
diode installation

A

diode installation

53
Q

If the frequency of the applied ac signal to a half-wave rectifier is 60 Hz, the frequency of the pulsating dc output will be
30 pps
60 pps
90 pps
120 pps

A

60 pps

54
Q

Thermal shutdown occurs in an IC regulator if:
power dissipation is too high
internal temperature is too high
current through the device is too high
load resistance increases

A

internal temperature is too high

55
Q

The conduction band is closest to the valence band in
semiconductors
conductors
insulators
The distance is the same for all of the above.

A

semiconductors

56
Q

With a half-wave rectified voltage across the load resistor, load current flows for what part of a cycle?
0 degrees
90 degrees
180 degrees
360 degrees

A

180 degrees

57
Q

Which of the following circuits would require the least amount of filtering?
A half-wave rectifier
A full-wave rectifier
A bridge rectifier
A full-wave rectifier and a bridge rectifier

A

A full-wave rectifier and a bridge rectifier

58
Q

The voltage where current may start to flow in a reverse-biased pn junction is called the
breakdown voltage
barrier potential
forward voltage
biasing voltage

A

breakdown voltage

59
Q

Providing a constant output regardless of ac input or load resistance changes is the function of a:
transformer
filter
regulator
rectifier

A

regulator

60
Q

When a diode is destroyed it has infinite impedance. When damaged by heat it will probably:
short
conduct more
conduct less
open

A

short

61
Q

The area at the junction of p-type and n-type materials that has lost its majority carriers is called the
barrier potential
depletion region
n region
p region

A

depletion region

62
Q

DC power should be connected to forward bias a diode as follows:
– anode, + cathode
– cathode, – anode
+ anode, – cathode
+ cathode, + anode

A

+ anode, – cathode

63
Q

At any given time in an intrinsic piece of semiconductor material at room temperature
electrons drift randomly
recombination occurs
holes are created
All of the above

A

All of the above

64
Q

In a power supply diagram, which block indicates a pulsating dc output?
transformer
filter
rectifier
regulator

A

rectifier

65
Q

List three diode packages:
clip package, DIP, small current package
DIP, small current package, large current package
small current package, large current package, and SIP
small current package, large current package, clip package

A

small current package, large current package, clip package

66
Q

The mimicking of an open/closed switch by a diode allows alternating current to be:
rectified
regulated
controlled
attenuated

A

rectified

terms ^^ (7 decks)

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