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Elementary Electrical Engineering (AC/DC) > Electrical Materials > Flashcards

Electrical Materials Flashcards

1
Q

parts or elements used in the making of any electrical construction project, developed and constructed for certain purposes

A

Electrical Materials

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2
Q

Classification of Electrical Materials in terms of Electrical Conductivity

A

conductors, insulators, semiconductors, superconductors

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3
Q

materials allowing for easy passage of free electrons

A

conductors

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4
Q

materials impeding the passage of free electrons

A

insulators

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5
Q

materials allowing for easy passage of free electrons and impeding the passage of free electrons

A

semiconductors

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6
Q

electric materials with some unique characteristics

A

superconductors

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7
Q

an object or type of material that permits the flow of electric charges from one particle to another

A

conductors

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8
Q

electrons of the atoms comprising a mass of metal are so uninhibited in their allowable energy states that they _________ between the different nuclei in the substance, readily motivated by any electric field.

A

float freely

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9
Q

sometimes described by scientists as an electron gas, or even an electron sea in which the atomic nuclei rest

A

electrons

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10
Q

electron mobility accounts for some of the other common properties of metals which are

A

good heat conductivity, malleability and ductility, lustrous finish when pure

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11
Q

Example of conductor materials

A

silver, gold, steel, sea water

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12
Q

What is a conductor’s current-carrying limit called?

A

ampacity

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13
Q

A wire with ________ resistance will dissipate a _______ amount of heat energy for any given amount of current.

A

greater, greater

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14
Q

Thin wires will, therefore, tolerate _____ current than thick wires.

A

less

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15
Q

Dissipated power due to a conductor’s resistance manifests itself in the form of _______.

A

heat

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16
Q

particles of the _______ do not permit the free flow of electric charges

A

insulator

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17
Q

The atoms in insulating materials have very _____ bound electrons, _______ free electron flow very well.

A

tightly, resisting

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18
Q

conductors current are in ______ to applied voltage

A

linear proportion

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19
Q

Threshold voltage is also known as

A

breakdown voltage or dielectric strength

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20
Q

Examples of Insulators

A

rubber, glass, oil, dry wood

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21
Q

voltage required to cause dielectric breakdown

A

dielectric strength

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22
Q

forcing current through an insulating material is called?

A

dielectric breakdown

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23
Q

an excellent insulating material and is very thin, allowing many turns of wire to be wound in a small space

A

enamel

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24
Q

materials that exhibit electrical behavior somewhere between that of conductors and that of insulators

A

semiconductors

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25
Q

exhibits intermediate conductivity

A

semiconductors

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26
Q

has more available charge carriers than an insulator but fewer than a conductor

A

semiconductor

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27
Q

Examples of semiconductor

A

silicon, germanium

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28
Q

Both silicon and germanium have ____ valence band electrons

A

four

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29
Q

state of an atom with four valence electrons available for covalent chemical bonding in its outermost electron shell

A

tetravalent atoms

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30
Q

What is the sharing of valence electrons called?

A

covalent bonding

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31
Q

makes it more difficult for materials to move their electrons into the conduction band

A

covalent bonding

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32
Q

can be used in the fabrication of resistors, capacitors, inductors, and—most importantly—transistors

A

semiconductors

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33
Q

can combine millions or even billions of transistors into one small package

A

integrated circuits

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34
Q

material that acts strangely when cooled down to a certain temperature

A

superconductors

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35
Q

when these materials are at that one special temperature, which we call the critical temperature, they suddenly become perfect conductors, means that their resistance is zero

A

superconductors

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36
Q

critical temperature is usually between

A

absolute zero and 10 Kelvin (between -273 Celsius and -263 Celsius)

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37
Q

discovered superconductivity in mercury (Hg) in 1911, for which he won a Nobel prize

A

Heike Onnes

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38
Q

Most metals ______ electrical resistance with decreasing temperature.

A

decrease

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39
Q

mercury (Hg) is unique in that its resistance abruptly drops to zero Ω at ______

A

4.2 K

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40
Q

Example of superconductors

A

lead, aluminum, tin, niobium

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41
Q

High temperature superconductors are compounds exhibiting superconductivity above the liquid nitrogen boiling point of ____ (-196.15 Celsius).

A

77 K

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42
Q

Two categories of classification of electrical components

A

Active components, passive components

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43
Q

components that supply and control energy

A

active components

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44
Q

components that respond to the flow of electrical energy and can dissipate or store energy

A

passive components

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45
Q

an electrical component that restricts the flow of current in the circuit

A

resistor

46
Q

the current flow through a resistor is _______ proportional to the voltage across the resistor terminals

A

directly

47
Q

a two-terminal linear passive component that is made from two conductive plates with an insulator between them

A

capacitor

48
Q

stores electrical energy when an electric charge is forced onto its terminals from a power source

A

capacitor

49
Q

allow for a measured resistance that can affect either voltage or current as calculated by using Ohm’s law

A

resistor

50
Q

maintains the charge even after getting disconnected from the power source

A

capacitor

51
Q

allow alternating current to flow through them and they resist the flow of direct current through them; able to stabilize almost any circuit

A

capacitors

52
Q

Two Types of Capacitors

A

polarized capacitors, non-polarized capacitors

53
Q

these capacitors have a positive and negative terminal

A

polarized capacitors

54
Q

these capacitors do not have any positive or negative terminals

A

non-polarized capacitors

55
Q

two-terminal passive electrical component; stores electrical energy in the form of magnetic energy

A

inductor

56
Q

comprises a conductor, commonly wound into a coil

A

inductor

57
Q

an electronic device, which consists of three terminals, made of semiconductor material

A

transistor

58
Q

controls the flow of voltage or current and acts as a switch for electronic signals

A

transistor

59
Q

a more advanced switch that has multiple output states; these states cannot be changed manually

A

transistor

60
Q

What do you use to control the output state of a transistor?

A

current

61
Q

an electrical device that is used to break the circuit, interrupting the current and to supply the current from one conductor to another conductor

A

switch

62
Q

works with the “on” and “off” mechanism

A

switch

63
Q

What does LED mean?

A

Light-Emitting Diode

64
Q

made from a semiconductor material that allows current to flow in one direction

A

diode

65
Q

blocks the current which tries to go against the flow in a wire

A

diode

66
Q

alternative of the diode

A

LED

67
Q

material or a piece of wire which is used to protect the components from destruction due to the excessive current flowing through them

A

fuse

68
Q

a fuse element is made out of

A

zinc, copper, silver, aluminum or alloys

69
Q

used to connect two or more devices, enabling the transfer of electrical signals or power from one device to the other

A

electrical wire/cable

70
Q

Allowable wire and cable types and sizes are specified according to the ________ and __________, with further restrictions on the environmental conditions.

A

circuit operating voltage, electric current capability

71
Q

a passive electrical device, consists of two coils of wire
linked by an iron core

A

transformer

72
Q

transfers electrical energy between two or more circuits

A

transformer

73
Q

transformer is also known as

A

transformer core

74
Q

offers the much needed capability of changing the current and voltage levels easily

A

transformer

75
Q

converts electrical energy from one circuit to another circuit with the help of mutual induction between the two windings without electrical connection between them

A

transformer

76
Q

converts power from one circuit to another circuit without changing the frequency but with a different voltage level

A

transformer

77
Q

an electrical device that is used to convert chemical energy into electrical energy through electrochemical discharge reactions

A

battery

78
Q

Two Types of Batteries

A

primary or disposable, secondary or rechargeable

79
Q

a component which converts mechanical energy into electrical energy by electromagnetic induction

A

generator

80
Q

an electrical generator that creates direct current using a commutator

A

dynamo

81
Q

an electrical generator that converts mechanical energy to electrical energy in the form of alternating current

A

alternator

82
Q

an electrical machine that converts electrical energy into mechanical energy

A

motor

83
Q

Examples of Electrical Measuring Instruments

A

ammeter, voltmeter, wattmeter, ohmmeter

84
Q

Classifications of Electrical Measuring Instruments

A

absolute instruments, secondary instruments

85
Q

instruments that give the value of quantity to be measured in terms of the physical constants of the instruments and their deflection only, not measurable on a graduated scale

A

absolute instruments

86
Q

instruments that are calibrated and directly give the value of quantity to be measured

A

secondary instruments

87
Q

instruments that are fitted with a pointer which moves over a calibrated scale and indicates the electric quantity to be measure directly on the scale

A

indicating instruments

88
Q

instruments that record the electrical quantity to be measure on a graph paper for a desired period

A

recording instruments

89
Q

instruments that measure the total quantity of electricity consumed in a circuit in a given time

A

integrating instruments

90
Q

Effects used in measuring instruments

A

magnetic effect, electrodynamic effect, electromagnetic induction effect, electrostatic effect, chemical effect, heating effect

91
Q

measures electric current

A

ammeter

92
Q

used to measure the potential difference or voltage of a circuit

A

voltmetera

93
Q

purpose is to extend the range of the ammeter by allowing it to measure current higher than its original full-scale value

A

shunt

94
Q

instrument to determine resistance

A

ohmmeter

95
Q

consists of a battery, a meter movement calibrated to read ohms, and a resistor

A

ohmmeter

96
Q

an adjustable resistor for zeroing and for correcting the aging of the battery

A

Ro

97
Q

unknown resistance to be measured

A

Rx

98
Q

a single instrument capable of measuring voltage, resistance, and current

A

multimeter

99
Q

most common multimeter

A

volt-ohm-milliammeter (VOM)

100
Q

A typical VOM has a meter movement with a full-scale current of ____ or a sensitivity of _____ when used as a dc voltmeter.

A

50 milliamperes, 20 kiloohms per volt

101
Q

used to measure milliamperes, dc voltage, ac voltage, and ohms

A

one-meter movement

102
Q

measure electrical quantities of current and voltage that change in amplitude and direction periodically with time

A

AC meters

103
Q

For frequencies below several hundred hertz, ________ that respond directly to ac excitation can be used.

A

electromechanical meter movements

104
Q

For higher frequencies, the ac quantities are first converted to dc and then applied to a _______.

A

D’Arsonval movement

105
Q

simplest type of ac voltmeter

A

Half-Wave Rectifier Circuit

106
Q

diode permits current to flow in one direction during the positive half-cycle and presents a very high resistance to current in the other direction during the negative half-cycle

A

half-wave rectifier circuit

107
Q

resulting current through the meter (AC meter) results

A

rms calibrated reading

108
Q

one way of improving the sensitivity of a rectifier type of ac meter is to use ______

A

full-wave rectification

109
Q

an instrument that measures dc power or real ac power

A

wattmeter

110
Q

uses fixed coils to indicate current in the circuit, while the movable coil indicates voltage

A

wattmeter

111
Q

The wattmeter is rated in terms of its

A

maximum current, voltage, power

Elementary Electrical Engineering (AC/DC) (9 decks)

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