Meters

Question 1

What device must be used with the D’Arsonval movement to enable the meter to read AC?

Answer 1

Rectifier

Question 2

What is meant by “damping” a meter movement?

Answer 2

smoothing it out or oscillating

Question 3

If you are using a multi-range meter and there is some doubt what the reading would be. What should you always do?

Answer 3

Read at the highest scale

Question 4

What could happen if your leads are reversed when measuring DC?

Answer 4

It could damage the meter

Question 5

What size of wire does a D’Arsonval movement have?

Answer 5

Very fine wires

Question 6

What is the max current that the D’Arsonval movement can handle without damage?

Answer 6

50mA

Question 7

What is it called when you get an incorrect reading because you are not looking at an analog meter straight on?

Answer 7

Parallax

Question 8

What does a multimeter read?

Answer 8

AC DC volts
AC DC amps
Ohms

Question 9

What is the purpose of a reset button in a multimeter?

Answer 9

To reset the internal circuit breaker

Question 10

What must be used with the D’Arsonval movement in order to read voltage?

Answer 10

Large resistor

Question 11

What is it called when a voltmeter changes the circuit that it is trying to read?

Answer 11

meter loading

Question 12

Rule of thumb. How much bigger should the resistance in the meter be to the load it is measuring?

Answer 12

10 times

Question 13

What should you check before connecting to a DC voltage source?

Answer 13

Polarity

Question 14

Before using a meter or tester, you should check what first?

Answer 14

The scale

Question 15

The common lead should always be what colour?

Answer 15

Black

Question 16

A voltmeter is rated 10kohms/v and the range selector switch is on 50v. What is the resistance of the meter? (Rm)

Answer 16

500,000ohms

Question 17

Meters are classified into 2 general groupings. What are they?

Answer 17

digital and analog

Question 18

What is one commonly used type of meter movement called?

Answer 18

D’Arsonval

Question 19

In what position should you store a meter if it does not have an off position?

Answer 19

highest AC volts setting

Question 20

What is the resistor called that is in series with the meter movement coil in a voltmeter?

Answer 20

multiplier

Question 21

Which meter would be more delicate? 1,000ohms/V or 10,000ohms/V

Answer 21

10,000

Question 22

Does a voltmeter have high or low resistance?

Answer 22

high

Question 23

Does an ammeter have high or low resistance?

Answer 23

low

Question 24

How is the resistor connected in a voltmeter?

Answer 24

parallel

Question 25

How is the resistor connected in an ammeter?

Answer 25

series

Question 26

What tester has 2 insulated test leads, a neon bulb, and a bulb holder?

Answer 26

Neon voltage tester

Question 27

Neon bulbs have high resistance and generally require at least _____ volts to initially switch on?

Answer 27

90 volts

Question 28

What is a more common name for a solenoid and plunger tester?

Answer 28

A wiggy

Question 29

What is the max amount of time that a solenoid and plunger should be connected to voltage sources?

Answer 29

20 seconds

Question 30

If the solenoid and plunger tester is vibrating, what does this mean?

Answer 30

It is measuring A/C

Question 31

When the electrode on the left side glows, the black test lead is?

Answer 31

negative

Question 32

when the electrode on the right side glows, the red test lead is?

Answer 32

negative

Question 33

What is the max amount of voltage that you can measure with a solenoid and plunger tester?

Answer 33

600v

Question 34

Which tester is used to check branch circuit receptacles?

Answer 34

an outlet analyzer

Question 35

In an ammeter, what is the resistor called to limit the current to the meter movement?

Answer 35

Shunt

Question 36

Where is the resistor located in the circuit?

Answer 36

parallel

Question 37

What must you do if you want to change the setting range on a multi-range ammeter?

Answer 37

turn it off

Question 38

What type of switch makes a new electrical connection before the previous one is turned off?

Answer 38

Make before break switch

Question 39

Which meter is more sensitive. 50microamps or 50milliamps?

Answer 39

50microamps

Question 40

What type of ohmmeter is the most common?

Answer 40

Series ohmmeter

Question 41

What is the fixed resistor for?

Answer 41

limiting current flow from exceeding ratings

Question 42

What is the rheostat for?

Answer 42

to compensate for low battery

Question 43

Which type of ohmmeter is used in a multimeter?

Answer 43

series

Question 44

What is the main advantage of the shunt type ohmmeter?

Answer 44

measures low resistances

Question 45

What is one disadvantage of the shunt ohmmeter?

Answer 45

the cell discharges when in use

Question 46

How can you tell the difference between series and shunt ohmmeters?

Answer 46

0 is on the left for shunt | 0 is on the right for series

Question 47

Give two applications that we would use an ohmmeter for?

Answer 47

measuring resistance | continuity tests

Question 48

What does a zero reading indicate?

Answer 48

short circuit

Question 49

what does an infinity reading indicate?

Answer 49

an open

Question 50

What is a megger used for?

Answer 50

measuring high resistances

Question 51

What are normal voltages a megger can put out?

Answer 51

250,500,1000v DC

Question 52

Most hand crank meggers have a clutch, what is it for?

Answer 52

Clutch will slip if voltage rating exceeds

Question 53

List 4 precautions when using a megger

Answer 53

- do not exceed rated values - high resistances only - do not touch leads - do not measure low voltage circuits

Question 54

In an ammeter, at what current must we use an external resistor?

Answer 54

25amps or more

Question 55

What would the external resistor of the ammeter be made out of?

Answer 55

copper

Question 56

What precautions should you take when testing circuits that contain capacitors?

Answer 56

discharge the capacitor if it holds a charge

Question 57

Why is an ohmmeter unsuitable for measuring insulation resistance?

Answer 57

the output voltage is too low

Question 58

If the leads of an ohmmeter are touching the pointer will read?

Answer 58

zero

Question 59

The AC clamp-on ammeter operates on the principle of which common device?

Answer 59

transformer

Question 60

In the ammeter the shunt is connected in___________ to the galvanometer?

Answer 60

parallel

Question 61

Why are larger shunts not placed within the case of the meter?

Answer 61

It would get too hot

Question 62

What is meant by meter loading?

Answer 62

It changes the values of the circuit

Question 63

Why do shunt resistors have low-temperature coefficient?

Answer 63

So they don’t change resistance when heated

Question 64

Neon type testers are usually not used on circuits less than?

Answer 64

90volts

Question 65

Sensitivity of Voltmeter?

Answer 65

50microamps to 50milliamps

Question 66

Sensitivity of ammeter?

Answer 66

5microamps to 50milliamps