E2 Digital Multi Meters
True or false : the bar graph has a polarity indicator on the left side ?
True
True or false; The bar graph acts like a needle on the analogue meter ?
True
List two advantages of a clamp on style ammeter over a DMM ?
Able to measure currents in excess of 10a, Circuit does not have to be de energized to take current measurement.
What is the wind on the DMM called where the reading appears ?
display
When using the diode test function to a silicon diode, if the diode is good a DMM will display the ________?
forward bias voltage drop
What are these false readings called ?
ghost or stray voltages
How can you extend the range of a digital clip on ammeter
more loops
List three types of electrical equipment that could have their insulation resistance tested ?
motors, transformers, cables, insulators
How is a voltmeter connected in a circuit ?
parallel
What are the two main types of displays for digital multi meters ?
LCD and LED
what is the minimum reading expected when meggering a motor conductor ?
1 megohm
What is the impedance value of most digital multi meters ?
10 Mega ohms
What is the typical input impedance of a digital multimeter ?
10 megaohm
Which DMM setting would used to measure the voltage output of a Alternator ?
AC Volts
What CSA standard covers workplace electrical safety ?
CSA Standard Z462 - 15
Identify one cause of false readings on a DMM on a de energized circuit.
Capacitive couplings
What category of dmm is required for testing where fault currents are very high?
Cat IV
What source voltage of the circuit is 120 Volts AC, and the resistance of the circuit 10 ohms. What type of ammeter would you use to measure the current in the circuit ?
Clamp on DMM max 10a
Which meter is used to take current measurement without opening the circuit ?
Clamp on ammeter
Which DMM setting would be used to measure the voltage output of a Rectifier ?
DC Volts
Which meters are more accurate: analogue or digital ?
Digital
Which meters are more commonly used in the electrical trade: Analogue or digital ?
Digital
What is the abbreviation DMM short for ?
Digital Multi Meter
What should always be done with a conductor before and after megger testing the conductor ?
Discharge each conductor to system ground
Which type of digital meter is best suited for electricians ?
Handheld DMM
When measuring voltage across a component, will meter loading cause the meter reading to be higher or lower than the voltage across the component without the meter in the circuit ?
Lower
List three causes of insulation deterioration
Mechanical damage, fault currents, excessive heat
If you are using the manual range and you see OL displayed, what does this mean ?
Overload
Which measurement function of a DMM requires an internal battery to provide current flow through the circuit ?
Resistance or ohms
List two applications where meggers are used
Routine maintenance programs, to verify conductors in raceways
How does a digital meter display its measurements ?
Segment display
How is a ammeter connected in a circuit ?
Series
What must be done before using DMM on a circuit ?
Test on a known circuit
What is the principle of operation of an AC/DC digital clamp on ammeter ?
The hall effect generator
The category rating of test leads should exceed the category rating of the DMM, true or false ?
True
Which of the two meter types, true rms or average responding would be used by an electrician testing an electronic ballast in a fluorescent lighting fixture ?
True RMS
Which meter is very popular ?
True RMS DMM
Which DMM function is used to measure current flow in an electrical circuit ?
ammeter
List three commonly available styles of digital meters.
cabinet, bench, handheld
Which meter function would be selected to provide quick and easy testing of whether a fuse is open or has a complete path through it ?
continuity
Which DMM function is used to measure resistance ?
ohmmeter
what must be done to get an accurate reading if OL appears on the display when the DMM is on manual range ?
switch to a higher range
Which feature of DMM would best be used to detect a rapidly changing signal such as contact bounce on a microswitch ?
the bar graph reading
Which feature of a DMM would best be used to detect a rapidly changing signal such as contact bounce on a microswitch ?
the bar graph reading