Using electrical and measuring instruments 204

Question 1

Digital meters are named such because

Answer 1

their internal circuits carry signals consisting of 1s and 0s

Question 2

An ADC is an essential part of

Answer 2

all digital meters

Question 3

Dual-slope integrators are found in certain kinds of

Answer 3

ADCs

Question 4

LCDs make better meter displays than LEDs because of their

Answer 4

lower energy requirement

Question 5

Ohms per volt is the measurement unit used to express a meter’s

Answer 5

sensitivity

Question 6

In order to generate a display, a digital meter needs a_____ processor, an ADC, and a readout control

Answer 6

signal

Question 7

All integrating ADCs count the time it takes to charge or discharge a capacitor to a reference

Answer 7

Voltage

Question 8

Which of the following is usually expressed as plus or minus some percentage and expresses a meter’s maximum and minimum expected error?

Answer 8

Accuracy

Question 9

D’Arsonval movements are used in______
meters.

Answer 9

analog

Question 10

All meters have one thing in common; they all have an internal_____ to which measured values are compared

Answer 10

standard

Question 11

The purpose of a make-then-break switch is to

Answer 11

protect the meter movement from overcurrent

Question 12

To connect an ammeter to a circuit, you need to

Answer 12

open the circuit

Question 13

The jaws of a clamp-on ammeter serve as a

Answer 13

transformer secondary

Question 14

Use clips on the ends of voltmeter leads whenever

Answer 14

voltage levels are high

Question 15

When the field coils of an electrodynamometer movement are connected in series with a circuit and the movable coil is connected in parallel, the instrument you have is a

Answer 15

wattmeter

Question 16

A parallel leg or branch added around an analog meter movement is known as a

Answer 16

shunt

Question 17

You will destroy an analog ammeter if you connect it

Answer 17

in parallel instead of series

Question 18

PMMC galvanometer meter movements for dc can be converted to measure ac with the addition of a(n)

Answer 18

rectifier

Question 19

The best way to take an ammeter reading on a live circuit is with a clamp-on ammeter, because you do not have to _____the circuit with this type of meter.

Answer 19

Break into

Question 20

An accurate wattmeter will always show the true power consumed, which takes into account the power losses due to the

Answer 20

Power factor

Question 21

Circuit resistance is measured by an)

Answer 21

Ohmmeter

Question 22

The symbol for infinity is

Answer 22

♾️

Question 23

An internal variable resistance is needed in an ohmmeter to

Answer 23

compensate for battery aging

Question 24

Dual shunts in an ohmmeter provide

Answer 24

dual-range capability

Question 25

To test the condition of the insulation on motor windings, use a(n)

Answer 25

megohmmeter

Question 26

Because resistance readings must be taken with the system power off, every ohmmeter must carry its own

Answer 26

Battery supply

Question 27

The current flowing through an ohmmeter is usually very small, on the order of ____ amperes

Answer 27

Micro

Question 28

When you need to measure very small resistances, use a _____ohmmeter. When you need to measure larger resistances, in the range of several kilo-ohms, use a series ohmmeter.

Answer 28

shunt

Question 29

The main tests you are likely to perform using a megohmmeter are for continuity, shorts, grounds, and for _____condition.

Answer 29

insulation

Question 30

A shorted capacitor will exhibit ______ resistance when tested with a megohmmeter.

Answer 30

little or no

Question 31

VOM stands for

Answer 31

volt-ohm-milliammeter

Question 32

Current and voltage readings taken on the far right of a meter's scale provide greater

Answer 32

accuracy

Question 33

In the GLITCH CAPTURE MODE, the meter is set so that you can view

Answer 33

transient spikes

Question 34

You should use a current probe with a multimeter whenever you need to

Answer 34

measure high-magnitude currents

Question 35

In a CAT Ill installation category, you would expect to find

Answer 35

three-phase motors and adjustable-speed drives

Question 36

The main advantage of an analog/digital multimeter is that it can allow you to _____more easily than with a DMM.

Answer 36

spot trends

Question 37

When using a multimeter to measure voltage, what should you do after turning on the device and turning the range selector to its highest voltage?

Answer 37

Check the meter on a known source

Question 38

Graphical multimeter can perform functions that standard digital multimeter cannot such as

Answer 38

Displaying transients

Question 39

Using a GMM in the TREND mode allows you to

Answer 39

monitor line voltage for sags and surges

Question 40

A chief cause of catastrophic multimeter failure is unexpected

Answer 40

Over voltage

Question 41

Transducers may be attached to an oscilloscope in order to

Answer 41

measure different kinds of signals

Question 42

If an oscilloscope does not have a free-running sweep, it will have a(n) ____ sweep

Answer 42

triggered

Question 43

A dual-trace oscilloscope is used to

Answer 43

display two waveforms at once

Question 44

An attenuating probe is used to minimize the effects of

Answer 44

circuit loading

Question 45

Square-wave signals are used in oscilloscopes to

Answer 45

compensate the probe

Question 46

Inscribed on the screen of most oscilloscopes is a pattern called a___ which provides a visual reference for measuring waveforms.

Answer 46

graticule

Question 47

Regardless of whether an oscilloscope is analog or digital, or single- or dual-trace, it can be either a real-time or a _______oscilloscope.

Answer 47

sampling

Question 48

The process of filling in the missing parts of a measured wave between sample points on an oscilloscope is called

Answer 48

interpolation

Question 49

Slope and trigger controls give you precise control over exactly where on the waveform you want the screen display to

Answer 49

begin

Question 50

Strong harmonics of the original sine wave frequency of 60 Hz can appear in an ac power line. They are usually caused by ______ loads.

Answer 50

nonlinear