Application Note

Special features
The following special features
and functions may make it easier
to use your DMM.
• Annunciators show at a
glance what is being mea-
sured (volts, ohms, etc.).
• One-switch operation makes
it easy to select measurement
functions.
• Overload protection prevents
damage to both the meter and
the circuit, while protecting
the user.
• Special high-energy fuses
provide extra protection for
user and meter during current
measurements and overloads.
• Autoranging automatically
selects proper measurement
range. Manual ranging lets
you lock into a specific range
for repetitive measurements.
• Autopolarity indicates neg-
ative readings with a minus
sign, so even if you connect
the test leads in reverse you
won’t damage the meter.
• Low battery indicator.
Fluke Corporation
PO Box 9090, Everett, WA USA 98206
©2006-2014 Fluke Corporation. All rights reserved.
Printed in U.S.A. 4/2014 2100079D_EN
Web access: http://www.fluke.com
7 Fluke Education Partnership Program ABCs of DMMs: Multimeter features and functions explained
Accessories and glossary
DMM accessories
One very important requirement
of a DMM is that it can be used
with a wide variety of acces-
sories. Many accessories are
available that can increase your
DMM’s measurement range and
usefulness, while making your
measurement tasks easier.
High-voltage probes and
current probes scale down high
voltages and currents to a level
the DMM can safely measure.
Temperature probes convert
your DMM into a handy digital
thermometer. RF probes can be
used to measure voltages at high
frequencies.
Furthermore, a selection of
test leads, test probes, and test
clips can help you easily connect
your DMM to the circuit. Soft and
hard carrying cases protect your
DMM and conveniently store
your accessories with your DMM.
Glossary
Accuracy. How close the DMM’s
displayed measurement is to
the actual value of the signal
being measured. Expressed as
a percentage of reading or as a
percentage of full scale.
Analog meter. An instrument
that uses a needle movement to
display the value of a measured
signal. The user judges the read-
ing based on the position of the
needle on a scale.
Annunciator. A symbol that
identifies a selected range or
function.
Average responding DMM. A
DMM that accurately measures
sinusoidal waveforms, while
measuring non-sinusoidal wave-
forms with less accuracy.
Count. A number used to specify
a DMM’s resolution.
Current-shunt. A low-value
resistor in a DMM for measuring
current. The DMM measures the
voltage drop across the current
shunt and, using Ohm’s Law, cal-
culates the value of the current.
DMM, digital multimeter. An
instrument that uses a digital
display to show the value of a
measured signal. DMMs feature
greater durability, resolution, and
far more accuracy than analog
meters.
Non-sinusoidal waveform. A
distorted waveform such as a
pulse train, square waves, tri-
angular waves, sawtooth waves
and spikes.
Resolution. The degree to
which small changes in a mea-
surement can be displayed.
rms. The equivalent dc value of
an ac waveform.
Sinusoidal waveform. A pure
sine wave without distortion.
True-rms DMM. A DMM that
can accurately measure both
sinusoidal and non-sinusoidal
waveforms.