Digital Multimeter Units 6-9 Flashcards
“DC voltage” is voltage that flows in _____ direction(s) only.
Answer 1: one
Answer 2: two
Answer 3: three
Answer 4: four
one
DC Voltage
The primary difference between alternating-current voltage and direct-current voltage is the _____.
Answer 1: shape of the sine wave
Answer 2: voltage source
Answer 3: amount of voltage drop on the circuits
Answer 4: voltage of the circuits
voltage source
DC Voltage
Direct-current voltages exceeding _____ are used in specialized applications such as small electric railway systems and large railway systems.
Answer 1: 90V
Answer 2: 110V
Answer 3: 125V
Answer 4: 180V
180V
DC Voltage
If DMM test leads do not match the polarity of the direct-current voltage point being tested, a(n) _____ sign appears to the left of the direct-current voltage measurement displayed.
Answer 1: negative
Answer 2: positive
Answer 3: equal
Answer 4: infinity
negative
DC Voltage
Direct-current voltage is measured with a DMM using standard procedures, the first of which is to set the function switch to AC voltage.
Answer 1: TRUE
Answer 2: FALSE
FALSE
DC Voltage Measurement Procedures
Unlike alternating-current voltages that can generally vary between -10% and +5% of the power source rating without causing any problems, even small direct-current _____ variations may indicate a problem.
Answer 1: amperage
Answer 2: voltage
Answer 3: a and b
Answer 4: none of these
voltage
Voltage Measurement Analysis
The exact amount of acceptable direct-current voltage variation depends upon the _____.
Answer 1: DMM being used
Answer 2: circuit
Answer 3: application
Answer 4: amperage of the circuit
application
Voltage Measurement Analysis
In some applications, direct-current voltage measurements may be taken in circuits that include alternating-current voltage.
Answer 1: TRUE
Answer 2: FALSE
TRUE
Voltage Measurement Analysis
On most DMMs, the resistance mode shares the function switch position with another DMM mode.
Answer 1: TRUE
Answer 2: FALSE
TRUE
Resistance
A DMM in resistance mode automatically begins to take a(n) _____ measurement, even before the test leads are connected to the component to be tested.
Answer 1: alternating-current
Answer 2: direct-current
Answer 3: resistance
Answer 4: continuity
resistance
Resistance
A DMM measures resistance with the _____ de-energized.
Answer 1: DMM
Answer 2: circuit
Answer 3: component
Answer 4: b or c
b or c
Resistance Measurement Procedures
The resistance measurement displayed by the DMM is the total resistance through all possible paths between the ______.
Answer 1: panel and the receptacle
Answer 2: test leads
Answer 3: voltage source and the DMM
Answer 4: none of these
test leads
Resistance Measurement Procedures
The resistance of all components connected in _____ with the component tested affects (usually lowers) the resistance reading.
Answer 1: series
Answer 2: parallel
Answer 3: series-parallel
Answer 4: any of these
parallel
Resistance Measurement Procedures
An open switch has continuity.
Answer 1: TRUE
Answer 2: FALSE
FALSE
Continuity
The main advantage of using the continuity test mode is that a(n) _____ response is sometimes more desirable than reading a resistance measurement.
Answer 1: audible
Answer 2: visible
Answer 3: vibrating
Answer 4: all of these
audible
Continuity
When testing for _____, the DMM beeps based on the resistance of the component under test.
Answer 1: resistance
Answer 2: capacitance
Answer 3: continuity
Answer 4: all of these
continuity
Continuity
“Current” is the amount of _____ flowing through an electrical circuit.
Answer 1: atoms
Answer 2: electrons
Answer 3: neutrons
Answer 4: protons
electrons
Current
An “ampere” is the number of electrons passing a given point in _____ second(s).
Answer 1: one
Answer 2: two
Answer 3: three
Answer 4: four
one
Current
A “clamp-on ammeter” is a meter that measures _____ in a circuit by measuring the strength of the magnetic field around a single conductor.
Answer 1: voltage
Answer 2: amperes
Answer 3: current
Answer 4: all of these
current
Current Measurement Procedures
The advantage of a clamp-on ammeter or a DMM with a clamp-on current probe accessory is that readings can be taken more _____ without opening or interrupting the circuit.
Answer 1: accurately
Answer 2: quickly
Answer 3: effectively
Answer 4: safely
safely
Current Measurement Procedures
Both clamp-on ammeters and DMMs with a clamp-on current probe accessory are commonly used to measure currents from _____.
Answer 1: 0.25A (or less) to 1,000A
Answer 2: 0.50A (or less) to 2,000A
Answer 3: 1.00A (or less) to 3,000A
Answer 4: 1.25A (or less) to 4,000A
1.00A (or less) to 3,000A
Current Measurement Procedures
Most DMMs have fuses that become part of the current-measuring _____.
Answer 1: function
Answer 2: test
Answer 3: circuit
Answer 4: none of these
circuit
Testing DMM Fuses
When using clamp-on ammeters, separate conductors under test from other surrounding conductors by a few _____ whenever possible.
Answer 1: inches
Answer 2: feet
Answer 3: yards
Answer 4: miles
inches
Clamp-On Ammeter Measurement Procedures
Care is required to protect the _____ when measuring alternating current or direct current with an in-line ammeter.
Answer 1: user
Answer 2: circuit
Answer 3: ammeter
Answer 4: all of these
all of these
In-Line Current Measurement Procedures
“Ohm’s law” is the relationship between voltage (E), current (I), and resistance(R) in a _____.
Answer 1: conductor
Answer 2: raceway
Answer 3: circuit
Answer 4: all of these
circuit
Ohm’s Law
Ohm’s law can be used for determining voltage, current, or resistance requirements _____.
Answer 1: during circuit design
Answer 2: for predicting circuit characteristics before power is applied
Answer 3: when using an in-line ammeter
Answer 4: a and b
a and b
Using Ohm’s Law
In troubleshooting applications, Ohm’s law can be used to determine how a circuit should operate and how it is operating under _____.
Answer 1: power
Answer 2: ideal conditions
Answer 3: testing scenarios
Answer 4: maximum use
power
Using Ohm’s Law
“Cold resistance” is the _____ of a component when operating current is not passing through the device.
Answer 1: continuity
Answer 2: resistance
Answer 3: capacitance
Answer 4: all of these
resistance
Using Ohm’s Law
_____ is the relationship between power (P), voltage (E), and current (I) in an electrical circuit.
Answer 1: Ohm’s law
Answer 2: The “power formula”
Answer 3: Kirchoff’s law
Answer 4: none of these
The “power formula”
Power Formula
The power formula is useful for determining expected current values because most electrical equipment lists a _____.
Answer 1: power rating
Answer 2: voltage
Answer 3: a and b
Answer 4: none of these
a and b
Using the Power Formula
Ohm’s law and the power formula are limited to circuits in which electrical continuity is the only significant opposition to the flow of current.
Answer 1: TRUE
Answer 2: FALSE
FALSE
Ohm’s Law and Impedance
“_____"”is the property of a circuit that causes it to oppose a change in current due to energy stored in a magnetic field.
Answer 1: Resistance (R)
Answer 2: Inductance (L)
Answer 3: Capacitance (C)
Answer 4: Impedance (Z)
Inductance (L)
Ohm’s Law and Impedance
