Test Instruments Midterm

What is the maximum allowable resistance for test leads?

1 ohm

Voltage unbalance should not be more than what percent?

1-2%

Current unbalance should not be more than what percentage?

10%

What is the symbol for ohms?

Omega

20. Which part of an analog multimeter display is determined by the position of the range switch?

Scale

What unit is used to measure frequency?

hz

Is a programmable controller a linear or nonlinear load?

nonlinear

Which test instrument is used to detect noise in an electrical signal?

oscilloscope

What type of fluctuation is a voltage increase of 12% for 78 sec?

overvoltage

Would a quality control testing lab be more likely to use permanent or portable test instruments?

permanant

What type of fluctuation is a voltage decrease of 15% for 32 sec?

sag

Which harmonic is 180 Hz?

third

In-line ammeters are used to measure small amounts of current.

true

Which electrical property equals current multiplied by resistance?

voltage

What type of voltage test instrument does not require direct contact with the circuit?

voltage indicator

How many electrical degrees separate balanced phases?

120 degrees

Which test instrument is used to test phase unbalance?

3 phase power analyzer

How many seconds can a momentary power interruption last?

3 seconds

A 1% current unbalance can create an 8% voltage unbalance.

False

What color is standard for grounding conductors?

Green

Would a maintenance technician who troubleshoots production equipment be more likely to use permanent or portable test instruments?

Portable

18. Surface leakage current is current that flows from areas on conductors where insulation has been removed to allow for electrical connections.

True

A high CAT rating indicates that a test instrument can be used in a circuit with high power, great possibility of short circuits, and high energy transients.

True

Both the function switch and the connection of the test leads must match the desired measurement before testing a circuit.

True

What colors are standard for neutral conductors?

White and natural gray

Which type of ammeter is used when the circuit to be measured cannot be opened?

clamp on

Which test instrument is designed to measure temperature at a point without contact?

infrared thermometer

Is an incandescent lamp a linear or nonlinear load?

linear

What is the abbreviation for milliamperes?

mA

The measurement hold mode is a multimeter mode that captures and stores the lowest and highest measurements for later display.

min max

Which common multimeter mode would be most useful in recording high- or low- voltage conditions over a period of time?

min max

Improper phase sequence reverses motor rotation.

true

Which type of meter, analog or digital, is more likely to be affected by electrical noise?

Digital

Which type of meter, analog or digital, is more likely to warn the user if the function switch is improperly set?

Digital

Leather protector gloves are used to protect wearers from electrical shock.

False

Tagout physically prevents energy sources from being energized.

False

The caution signal word indicates an imminently hazardous situation that, if not avoided,results in death or serious injury.

False

Which two temperature scales are most commonly used by test instruments?

Farenheit/celsius

What unit is used to measure capacitance?

Farods

Which unit prefix indicates one million times the base unit?

Mega (M)

Which unit prefix indicates one thousandth of the base unit?

Milli

Which organization publishes the National Electrical Code®?

NFPA

19. Which type of AC voltage measurement is useful because it equates the heat produced by an AC sine wave to DC resistive circuit?

RMS

Digital meters are more popular than analog meters because digital meters typically have greater measuring capabilities.

True

Loads such as motors and solenoids decrease in resistance over time

True

Test instruments should be periodically tested for accuracy.

True

What electrical unit is used to rate rubber insulating gloves?

Voltage

What color is the test lead that typically indicates negative or ground?

black

Which multimeter test mode is commonly used to test components such as switches, uses, electrical connections, and individual conductors?

continuity

Which electrical property is measured to indicate total circuit loading?

current

What type of electronic component is tested by measuring the voltage drop across it in two directions?

diode

480 Hz is a triplen harmonic.

false

Harmonics are produced by linear loads.

false

High voltage unbalances can be created by small current unbalances.

false

What type of additional personal protective equipment must be worn when working around electrical systems with a risk of arc flash?

flash suit

Which common multimeter mode would be most useful in measuring the change in current when a load is turned ON?

relative

Which common multimeter mode records a mensurement and displays the difference between the reading and subsequent measurements?

relative mode

Nonlinear loads are a common source of harmonic problems.

true

Reverse the polarity of the test leads when a negative sign is displayed at the beginning of a multimeter bar graph.

true

Some motors can continue to operate on only two out of three phases.

true