Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

B1 Modules > Module 3 > Flashcards

Module 3 Flashcards

1
Q

What is potential difference

A

A potential difference always arises between two differently charged points. An electrical voltage occurs, as soon as there is a deficiency of electrons at one point and an excess of electrons in another point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What device is used to separate charges

A

A generator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are current transformers

A

Current transformers (CTs) are special transformers which allow the measurement of AC currents without breaking the current-carrying leads.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the charge of a single electron

A

0.1602x10 to the -18

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A charged atom is said to be what

A

Ionised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a molecule

A

A molecule is an electrically neutral group of two or more atoms held together by chemical bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a cation

A

A positively charged ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an anion

A

A negatively charged ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How are molecules held together

A

Covalent bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are ionic compounds held together

A

Ionic bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are intermetallic compounds held together

A

Metallic bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Generally how many electrons do good conductors have in the outer valence orbit

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are insulators also known as

A

Non conductors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

During static electricity what are free electrons

A

Electrons in the outer layer that can be handed to the other material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is charging by induction

A

A charged rod is placed near a metal bar it steals the charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Coulomb’s law

A

Opposites attract and likes repel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What temperature must cables not exceed

A

60°c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is pure water a conductor

A

No

Tap water is due to the amount of impurities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is electrolysis

A

The decomposition of chemical compounds by passing an electrical current through a liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the conducting substance called in the electrolysis process

A

Electrolyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can be done with an oscillograph

A

Processes in electrical engineering can be recorded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What can be done with an oscilloscope

A

Processes can be visualised but not recorded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is the electron beam oscilloscope used today

A

Easy to operate, versatile and shock resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a potential difference

A

A potential difference arises between two differently charged points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is voltage generated

A

By separating positive and negative charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is Electromotive force (EMF)

A

Also known as voltage

The difference in energy between electrical charges or potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a voltage called if it has the same polarity over time

A

DC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the two different ways of indicating measured voltage

A
  • A pointer deflection (analogue meter)
  • Numerical read out (digital meter)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is electrical current

A

The flow of electrical charges in a certain direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

When measuring current with an ammeter which current must you connect positive to positive and negative to negative

A

DC current

AC current doesn’t matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is breaking action

A

Breaking action of a conductive material is dependant on the atomic density of the material. The greater the spacing of the ions the smaller the breaking action becomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What’s is charge (Q) unit

A

Coulomb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is conventional current flow

A

Current flows from the positive to negative poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is different in current flow in metals apposed to other materials

A

The electrons move because of the construction of the material and this is called electron flow from negative to positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How is electricity produced by light

A

When light is shone on certain semiconductors such as silicon or germanium charge separation happens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are photocells

A

Generators of electrical voltage through light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is electron emission

A

The separation of electrons from a bonding metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the process called for emitting electrons by heat

A

Thermonic emission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Voltage generation by heat is used for what?

A

Measuring EGT for an aircraft turbine engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How is a voltage generated with a Piezo Chrystal

A

It is deformed by using pressure and is called the piezoelectric effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is used in dynamometers

A

The piezoelectric effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the most important form of voltage generation in engineering

A

Induction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the operating principle in all generators

A

Induction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is “capacity” of a DC primary cell

A

The quantity of electricity (charge in Q in ampere hours)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Can primary cells be recharged or reused

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Can secondary cells be charged or reused

A

Yes, they are used in aircraft, cars, laptops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are batteries capacity rated in

A

Ampere hours (Ah)

48
Q

What voltage do lead acid cells have when fully charged

A

2v and 1.83 final discharge voltage

49
Q

What is the voltage of Nickel Cadmium (NiCad) cells when fully charged

A

1.2v and fall to 1v when discharged

50
Q

When is the electrolyte level in a Nickel cadmium battery at its lowest

A

After discharge

51
Q

What is the combination of cells called

A

A battery

52
Q

In a parallel circuit how do you find out the total resistance

A

It’s lower than the lowest individual resistance

53
Q

When does a batteries IR become greater

A

As the battery discharges

54
Q

A batteries IR is equal to what?

A

The difference between the open circuit voltage (OCV) and the closed circuit voltage (CCV)

55
Q

What materials make up thermocouples

A

Chromel and alumel

56
Q

What temp range do thermocouples normally measure

A

-200 to 2300°c

57
Q

What are thermocouples normally used for

A

To measure EGT of jet engines

58
Q

What is OHMs law

A

The relationship between Current, Voltage and Resistance

59
Q

What is Kirchhoffs first law

A

At any point in an electrical circuit, the sum of currents flowing towards that point is equal to the sum of currents flowing away from that point

60
Q

What are the most commonly used resistors

A

Fixed value resistors

61
Q

What is the most common axial lead resistor

A

The carbon film

62
Q

What is the carbon film resistor used for

A

Applications where a very good tolerance and temperature coefficient are not necessary

63
Q

If you have a resistor with a wire 3 times longer than normal will the resistance be higher or lower or the same

A

3 times higher

64
Q

What is resistance measured in

A

Ohms

65
Q

When would a potentiometer be used

A

Where there needs to be a variation of voltage

66
Q

When would a rheostat be used

A

In circuits where a variation in current is required

67
Q

What are the two types of mechanically varied resistors that are in common use

A

Potentiometer and Rheostat

68
Q

What very sensitive meter is used in a Wheatstone bridge

A

A galvanometer

69
Q

What are voltage dependant resistors

A

The resistance value changes according to the applied voltage

70
Q

What is a Wheatstone bridge

A

A type of electrical scale

71
Q

What does a Wheatstone bridge consist of

A

It compares the resistance of two resistors and consists of two series connectors in parallel

72
Q

What very sensitive meter is used inside a Wheatstone bridge

A

A galvanometer

73
Q

Where are preset rheostats commonly mounted

A

Printed circuit boards and are normally preset at manufacturing

74
Q

What is power

A

Power is the rate at which work is performed

75
Q

What is the standard unit of electrical power

A

The Watt

76
Q

What is the measure of charge

A

The coulomb

77
Q

What is charge denoted by

A

Q

78
Q

What is current measured in

A

Ampere

79
Q

What is current denoted by

A

I

80
Q

What is Hertz

A

For AC power, the amount of times per second the frequency goes back and forth

81
Q

What is potential difference measured in

A

Volts

82
Q

What is resistance measured in

A

Ohms

83
Q

What is power measured in

A

Watts

84
Q

What is energy measured in

A

Joules

85
Q

What type of energy is created when current flows through a resistor

A

Heat

86
Q

What do capacitors normally consist of

A

Two metal plates or foils that are insulated from each other

87
Q

The charge that can be held by a capacitor depends on what

A

The plate area, distance between plates and the applied voltage

88
Q

What is the unit of capacitance

A

The Farad

89
Q

What increases the electric field inside a capacitor

A

The dialectic used

90
Q

How does a capacitor hold a charge

A

A charge is applied between two plates which creates an electric field. The amount of charge it holds is directly proportional to the voltage applied

91
Q

What capacitors can be used with AC and DC circuits

A

Paper or film capacitors

92
Q

Where would old variable capacitors be used

A

Old fashioned radios

93
Q

When adding a new uncharged capacitor into a circuit what would be used to prevent the current being too high

A

A resistor will be used

94
Q

What are capacitance time constants

A

The higher the capacitance the longer the charging time will be. The higher the resistance the longer the charging time will be

95
Q

When a capacitor charges how much does it get charged by in its first cycle

A

63% and will keep being topped up by 63% until by the 5th time it will be fully charged

96
Q

How would you visually inspect a capacitor

A

Looking for bulging of the capacitor and electrolyte leakage

97
Q

Up to 40% of defective capacitors suffer from what

A

Excessive leakage current

98
Q

What defect do 25% of capacitors suffer from

A

Dielectric absorption

99
Q

What are the lines of magnetic force called produced by a magnet

A

Flux

100
Q

What materials are magnets normally made of

A

Steel or alloys of steel

101
Q

All magnets have areas where their magnetism is particularly high. What is this area called

A

The poles

102
Q

In the middle of a magnet there is an area with no attractive force, what is it called

A

The neutral zone

103
Q

How can a metal be demagnetised

A

Heating above the curie temperature
Mechanical force

104
Q

What is degaussing

A

Slowly moved away from a strong alternating magnetic field

105
Q

What is a disadvantage of demagnetisation by heating beyond the curie temperature

A

If the temp falls below magmatism can re occur

106
Q

What is magnetomotive force denoted by

A

The Greek letter theta

107
Q

How can the magnetic field of a current carrying coil be multiplied

A

By inserting an iron core into the cavity

108
Q

What are magnetically hard materials

A

Materials that are hard to magnetise or demagnetise

109
Q

What is “remanence” when talking about magnetic items

A

When a material is removed from a coil it is still slightly magnetic and that is called remanence

110
Q

What is retentivity

A

The ability of a material to be abe to retain residual magnetic field

111
Q

What is the main purpose of a filter

A

They suppress certain frequencies out of a certain frequency composition and let certain other frequencies pass undamped

112
Q

What’s special about CR filters

A

They are commonly used because of their compact design and lower price

113
Q

Are LR filters used often or not often

A

They are rarely used

114
Q

What is the series connection of a high pass filter and a low pass filter

A

A band pass filter

115
Q

What is the parallel connection of a high pass filter and a low pass filter

A

Band stop filter

B1 Modules (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions