Brainscape's Knowledge GenomeTM

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


See full index

Electrical theory > Quiz 2 > Flashcards

Quiz 2 Flashcards

0
Q

What is an electromagnet?

A

A non magnetic material that takes on the characteristics of a magnet whenever electrical current is passed through

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

Important date to remember?

A

Hans Christian Oersted, 1819

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

Left hand rule?

A

Point the thumb in the direction of electron flow and the fingers will wrap in the orientation of flow

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

Why are the lines of flux of a single conductor not useful?

A

They have no polarity and are too weak to be useful.

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

What are the two ways flux strength can be increased?

A

Increasing the current through the conductor, increasing the density of the lines of flux.

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

Flux density can be increased in what two ways?

A

By wrapping conductor in a coil, inserting a highly permeable core

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

what are the advantages to forming a coil?

A

The strength of the flux is increased , and gives the flux polarity

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

Left hand rule for coils?

A

Wrap the fingers of the left hand around the coil in the direction of electron flow, the thumb will point to the North Pole

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

In what two ways can the polarity of a coil be reversed?

A

Reverse the current flow through the conductor, reverse the direction of the wraps.

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

Measurements of flux?

A

Gilbert and amp turn

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

What is the advantage to having an electromagnet?

A

It has the characteristics of a natural magnet which can be controlled, both strength and polarity

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

Uses for electromagnets?

A

Relays, solenoids, generators, alternators, motors

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

Difference between a relay and a solenoid?

A

Relay uses a non movable core

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

What is a relay/solenoid?

A

An electrical switch which is operated by an electromagnet

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

What is the purpose of a relay?

A

To use a small amount of current to control a large amount of current

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

What is a generator/alternator?

A

A device which uses an electromagnet to generate electricity

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

Difference between a generator and an alternator?

A

In a generator the electromagnet does not spin

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

What is a motor?

A

A device in which two electromagnets with fields that repel each other and cause one of them to spin

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

What are the sources of electricity?

A

Magnetism, chemical, heat, pressure, light.

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

Example of magnetic power?

A

Alternator, generator

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

Example of chemical power?

A

Batteries

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

Example of thermal power?

A

Thermocouples

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

Example of pressure power?

A

Record needle

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

Example of light power?

A

Solar panels

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

What is the definition of a complete circuit?

A

An electrical circuit where there is a complete path from the source, to the load, and back to the source.

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

What is a source?

A

The part of the circuit that provides the potential for electron transfer.

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

What is a conductor?

A

The path by which electrons flow from the source, to the load , and back to the source.

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

What is the major consideration for choosing a material for a conductor?

A

Weight versus resistance

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

What are factors effecting resistance?

A

Resistivity, positive temperature coefficient of resistance, dimension of the conductor.

29
Q

What is the cross sectional area of a conductor given in?

A

Circular mils.

30
Q

Formula for circular mils?

A

a=D^2

31
Q

What is the conversion between square mils and circular mils?

A

.7854

Square to circular divide by .7854

32
Q

What is a load?

A

Any device designed to drop voltage

33
Q

What is the purpose of switches?

A

To control the routing of electron flow.

34
Q

Switch classifications?

A

SPST, SPDT, DPST, DPDT.

35
Q

Types of switches?

A

Toggle, slide, rocker switch, wafer switch

36
Q

What is the purpose of precision and micro switches?

A

Activated by mechanical means, to show position.

37
Q

What is the purpose of protective devices?

A

To protect the wiring from excessive current

38
Q

What is a fuse?

A

A fusible like with a low melting point alloy

39
Q

What is a normal blow fuse?

A

Opens as soon as the excess current condition is exceeded

40
Q

What is a slow blow fuse?

A

A fuse designed to allow the rated current to be exceeded for a short period of time before the fuse opens

41
Q

Three types of circuit breakers?

A

Automatic resetting circuit breaker, manual setting circuit breaker, trip free circuit breaker

42
Q

What is the only

Type of circuit breaker approved for aviation?

A

Trip free circuit breaker

43
Q

Types of controlling mechanisms for circuit breakers?

A

Thermal and magnetic.

44
Q

What is the purpose of resistors?

A

They are used in some applications to control voltage and in some applications to control current.

45
Q

How does a resistor dissipate power ?

A

In the form of heat

46
Q

Types of resistors?

A

Variable and carbon resistor.

47
Q

Rheostat?

A

One circuit

48
Q

Potentiometer?

A

Two circuits.

49
Q

Types of carbon resistor?

A

Axial load and radial load resistor

50
Q

How is the nominal value of a carbon resistor given?

A

By the color bands based on codes established by the electrical industries associates

51
Q

Axial lead resistor designations?

A 
1st band, 1st significant digit
2nd band, 2nd significant digit
3rd band, number of zeros (multiplier)
4th band, the tolerance.
If no fourth band, tolerance is 20%
52
Q

Radial lead resistor designations?

A

Body color- first significant digit
Large band- second significant digit
Dot- the number of zeros
Stripe- the tolerance

53
Q

In a carbon resistor what determines the resistance rating in ohms?

A

The composition and the size determines the wattage rating

54
Q

What is a wire wound resistor?

A

A special type of resistor designed to dissipate large amounts of power

55
Q

What is a film resistor?

A

A special kind of resistor designed to dissipate very small amounts of power

56
Q

What is an open circuit?

A

A circuit where there is not a complete path from the source through the load and back to the source

57
Q

What is a logic circuit?

A

A binary circuit with one of two outcome possibilities

58
Q

Name the types of logic circuits

A

AND OR NAND NOR EXCLUSIVE

OR

59
Q

Black?

A

0, -

60
Q

Brown?

A

1,1

61
Q

Red?

A

2,2

62
Q

Orange?

A

3,3

63
Q

Yellow?

A

4,4

64
Q

Green?

A

5, .5

65
Q

Blue?

A

6, .25

66
Q

Violet?

A

7, .1

67
Q

Gray?

A

8, -

68
Q

White?

A

9, -

69
Q

Gold?

A

-, 5

70
Q

Silver?

A

-, 10

71
Q

No color?

A

0, 20

Electrical theory (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions