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Module 7 > 7C > Flashcards

7C Flashcards

1
Q

4 electrical variables to be measured

A

Voltage, Current, Resistance, Power

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2
Q

Advantages of analogue meters over digital

A

Easier to identify trends with the sweeping needle

Analogue meter doesn’t read ‘ghost’ voltages

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3
Q

explain how the d’Arsonval meter works

A

A coil moves in proportion to a magnetic field created by the current you are measuring. The coil is connected to a needle which indicates on the analogue meter. A spring is attached to the needle and coil which brings it back to neutral when no current is applied

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4
Q

Ammeter is connected to the test load in series, however internally the ammeter measures in parallel. T or F

A

True

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5
Q

DC ammeters are not sensitive to current direction? T or F

A

False

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6
Q

Shunts are connected in series or parallel to ammeters

A

Parallel

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7
Q

How does a multi range ammeter differ to a normal ammeter

A

A multi range ammeter has multiple shunts with varying resistances. You can manually select the resistance you want so you can measure a range of current ratings without cooking the device

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8
Q

For multi range ammeters you should always start at the lowest current range and work your way up to the required range to not blow up the machine. T or F

A

False

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8
Q

Voltmeters should be connected in parallel. T or F

A

True

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9
Q

What is the difference between a DC and AC meter?

A

An AC meter has a rectifier to convert AC power to DC for reading

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10
Q

What current does a safety ohmmeter use

A

0.5mA

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11
Q

How must you calibrate an Ohmmeter

A

Short the ohmmeter and then adjust the rheostat to get a ‘zero’ reading

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12
Q

characteristics of a megohmmeter

A

A regular ohmmeter with a step up transformer to greatly increase voltage. low current

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13
Q

What is the point of a Current Transformer

A

to measure current flow at levels which would otherwise be beyond the range of the meter

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14
Q

Benefits of a clamp meter

A

you can conveniently measure the current of any wire by enclosing the clamp meter around the wire

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15
Q

Generally, how often is a calibration required

A

1 year

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16
Q

Logic probes are used for:

A

trouble shooting in logic circuits by indicating whether certain parts of the circuit are hi or low

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17
Q

What is RMS

A

a way to compare DC to AC power. It is the point of an AC wave where the power output is the same as DC power. It is always 0.707x the AC peak

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18
Q

Signal generators are used to;

A

test and align all types of transmitters and receivers

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19
Q

What is an attenuator

A

Device that reduces the amplitude or power of a signal without distorting the waveform

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20
Q

How does a time domain reflectometer measure where along the cable the error is?

A

the time taken for a signal to reach the end of a known length of cable is a known value. When a signal is received in a shorter amount of time, the speed of light and time to receive this signal is used to figure out how far away from the measurement the error in cable is.

21
Q

Pitot static testers;

A

consists of applying pressure into the pitot tubes at a controlled rate to check whether the pitot tubes are measuring and reading data correctly

22
Q

Turbine temperature tester works by

A

applying a temperature to the thermocouples to ensure they are reading data correctly

23
Q

Fuel quantity indication test sets work by

A

creating a fake capacitance signal on fuel sensing probes

24
Q

Why should you ensure Fuel quantity indication test sets are grounded

A

fuel and sparks do not mix

25
Q

Loop resistance testers analyses circuits of cables by;

A

measuring resistance at two locations within a cable loop to check for corrosion

26
Q

Circuit tests normally include

A

Bonding testing
Continuity testing
Insulation resistance testing
Functional testing

27
Q

If arcing is detected you should

A

check bonding straps for corrosion

28
Q

How to test a bonding meter

A

Short the three prongs on both probes to obtain a zero reading

Short two prongs of the double prong probe to obtain full deflection

29
Q

For general electrical bonding, what is the max lead resistance

A

0.1 Ohms

30
Q

Why should you use copper terminations on copper wire and aluminium terminations on aluminium wire?

A

to prevent dissimilar metal corrosion

31
Q

What class crimping tools, lugs and splices should not be used on aircraft

A

Class 2

31
Q

How do hand crimping tools prevent half crimps

A

Most have a self locking ratchet which prevents the tool from opening until the crimp is complete

32
Q

Order of colour determining wire gauge sizes

A

Yellow (smallest), Red, Blue (largest)

33
Q

What is the point of the abrasive compound inside an aluminium wire termination

A

during crimping, the compound releases and cleans the oxide film on the aluminium to avoid corrosion

34
Q

What should you inspect a crimped termination for?

A

Crimp indent centred on the terminal lug barrel

Indent in line with the barrel

Terminal lug not cracked

Terminal lug insulation not cracked

Insulation grip crimped

35
Q

What are splices used for

A

When a wire splits in the middle and needs to be reconnected

36
Q

Standard practices for splicing

A

splices must be visable for future inspection

on bundles of wires requiring multiple splices, space the splices out to ensure bundle size doesn’t increase

usually only one splice per wire

should not be used within 12in of termination

37
Q

What is the max bend radius of a coax cable

A

6 times the diameter of the cable

38
Q

Max number of wires in a bundle

A

75 or 5cm diameter

38
Q

Max distance between cable identifiers

A

15in

38
Q

Max bend radius of a regular cable, supported and unsupported

A

10x diameter unsupported
3x diameter supported

39
Q

What should be installed when a wire passes through a bulkhead or wall cutout with less than 1cm clearance

A

a gommet around the wall

40
Q

Wires must be be spaced as far away as possible from plumbing lines. T or F

A

True

41
Q

The purpose of flux is to

A

remove oxidation during soldering

41
Q

Hard solders are used for

A

Situations where greater mechanical strength or exposure to higher temps is required (e.g. Thermocouples)

42
Q

Flux core solder is

A

A solder wire with a channel of rosin flux inside, providing a convenient and controlled flux application

43
Q

Heat sinks are used for

A

absorbing unwanted conducted heat before it reaches the hear sensitive circuitry around the joint you’re soldering

44
Q

How long do you have to clean flux residue post soldering

A

1 hour

44
Q
A
45
Q

What is the most efficient soldering iron temp for general use

A

240-270

46
Q
A

Module 7 (6 decks)

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