Electrical System Flashcards
1
Q
Electrical current measurement
A
Amps
2
Q
Amps measures…?
A
Electrical current
3
Q
What is electrical current?
A
Rate of flow of electric charge
4
Q
Rate of flow of electric charge is known as?
A
Current
5
Q
What is needed to make a current flow through a component?
A
Potential difference (voltage)
6
Q
Voltage is also known as..?
A
Potential difference
7
Q
What current comes from a battery or generator?
A
DC
8
Q
What converts DC to AC?
A
Inverter
9
Q
What does an inverter do?
A
Converts DC to AC
10
Q
What type of current flows only in one direction?
A
DC
11
Q
Voltage measures what?
A
The force driving electricity through a circuit
12
Q
What is the reciprocal of resistance?
A
Conductivity
13
Q
What is the reciprocal of conductivity?
A
Resistance
14
Q
Ohm’s Law
A
V = IR
15
Q
What symbol represents current?
A
I
16
Q
The symbol I represents what?
A
Current
17
Q
An AC current changes its flow at regular intervals known as?
A
Cycles
18
Q
What is a complete cycle of an AC current?
A
Current flowing to a maximum and minimum point then back to 0
19
Q
What is frequency?
A
Rate at which AC changes direction
20
Q
What does Hertz essentially mean?
A
Cycles per second
21
Q
Measurement of frequency is?
A
Hertz
22
Q
Cycles per second is known as?
A
Hertz
23
Q
What changes AC to DC?
A
Rectifier
24
Q
What does a Rectifier do?
A
Changes AC to DC
25
What voltage is easier to produce? AC or DC?
AC
26
What is amplitude?
Maximum value of a wave relative to zero
27
What is the maximum value of a wave relative to zero known as?
Amplitude
28
What is a Phase?
Position in the waveform relative to 360 degrees
29
In teerms of phases, how many degrees is one complete cycle of a wave?
360
30
Frequency and wavelength relationship type?
Inverse
31
Frequency and wavelength relationship?
Higher frequency = Shorter wavelength
32
What symbol represents one wavelength?
Lambda
33
An electric current passing through a coppeer wire does what?
Generates a magnetic field
34
What is the electrical system typically in a light aircraft?
DC
35
What must be done to electricity generated by an aircraft's alternator?
It must be rectified into DC
36
What connects a batteery/alternator and an aircraft's various electrical components?
Bus bar
37
If a Bus bar is Earthed, what does that mean for an aircraft's electrical components?
They are also Earthed
38
What is Common Earth?
Thee notion that aa Bus Bar's components are Earthed due to the Bus Bar being Earthed
39
What is the 'exhaust' of a typical battery?
Hydrogen and oxygen
40
The 'exhaust' of hydrogen and oxygen from a charging battery means what for its storage?
It must be vented
41
When is the largest current draw on the battery?
Start-up
42
For batteries in series, what is added together?
Voltage
43
How are battery voltages added together?
In series
44
For batteries in parallel, what is added together?
Capacity
45
How are battery capacities added together?
In parallel
46
Aircraft batteries are typically arranged in what system?
Parallel
47
What remains constant for batteries in parallel?
Voltage
48
What changes for batteries in parallel?
Amps
49
Where must battery fluid be in relation to its plates?
The fluid should coveer the plates
50
How is electricity generated in a generator?
Moving a wire armature within a magnetic field
51
The output of a compound wound generator is relatively...?
Constant
52
How is a generator electrically self-sufficient?
It has its own permanent magnetic field
53
Why is an alternator not electrically self-sufficient?
It doesn't have a permanent magnetic field
54
What current does a generator produce?
AC
55
Principles of an alternator?
Magnetic field spins within a wire
56
What characterises the wires of an alternator (known as the stator)?
They are stationary
57
What is a stator?
Stationary set of wires in an alternator
58
What rectifies AC in an alternator?
Diodes
59
What do diodes do in an alternator?
Rectify AC into DC
60
How do diodes rectify in an alternator?
They only permit one direction of flow
61
What is the secondary operation of a diode in an alternator?
Preventing reverse current flow from the battery into the alternator
62
What controls the flow of current in an alternator?
Diode
63
What is the relationship between an alternator's voltage and battery voltage?
The alternator voltage is marginally higher than the battery voltage
64
Why is the alternator voltage marginally higher than the battery voltage?
To allow the battery to be fully recharged
65
What system characteristic allows an aircraft battery to be fully recharged?
Alternator voltage is higher than the battery voltage
66
What are thee main advantages of an alternator?
Provides constant electrical output
Lighter than generators
Easier to maintain
67
What is the principle disadvantage of an alternator?
It requires an initial current to create a magnetic field
68
Significant issue with an alternator's setup of a magnetic field spinning within a wire?
The magnetic field requires a battery
69
Current out of a battery is known as?
Discharge
70
What is discharge?
Current out of a battery
71
Solenoids are used in what electrical device?
Relay
72
How is a typical relay contact held open (meaning the circuit is incomplete)?
By a spring
73
What is often the cause of an excessive current?
Faulty voltage regulator
74
What component prevents excessive currents?
Voltage regulator
75
What type of material prevents electrostatic charge from dissipating easily?
Insulator
76
What type of material allows electrostatic charge to dissipate easily?
Conductor
77
A continuous conducting path on an aircraft is essential to preventing what?
Differential electrical charge between parts that can produce sparks
78
What is necessary to prevent differential electrical charge between parts that can produce sparks?
Continuous conducting path
79
What components ensure conducting paths are continuous on aircraft?
Bonding wires
80
What key component prevents differential electrical charge on aircraft?
Bonding wires
81
What dissipates static charge into the atmosphere?
Static wickss
82
What do static wicks do?
Dissipate static charge
83
In terms of electricty, what kind of material are aircraft tyres?
Conductors
84
What do aircraft tyres do on landing in relation to electricity?
Earth built-up static electricity
85
What kind of instruments are not electrically powered?
Pitot-static instruments
86
Are pitot-static instruments electrically-powered?
No
