7
Setting the Range
Two of the most commonly asked ques-
tions about digital multimeters are What
does Range mean? and How do I know
what Range the multimeter should be
set to?
What Does Range mean?
Range refers to the largest value the
multimeter can measure with the rotary
switch in that position. If the multimeter
is set to the 20V DC range, then the
highest voltage the multimeter can mea-
sure is 20V in that range.
EXAMPLE: Measuring Vehicle Battery
Voltage (See Fig. 1)
Now assume we set the multimeter to
the 2V range. (See Fig.
2)
The multimeter display now shows a
“OL” and nothing else. This means the
multi-meter is being overranged or in
other words the value being measured is
larger than the current range. The range
should be increased until a value is
shown on the display. If you are in
the
highest range and the multimeter is
still showing that it is overranging,
then the value being measured is too
large for the mul-timeter to measure.
How do I know what Range the mul-
timeter should be set to
?
The multimeter should be set in the
lowes t po ssibl e rang e witho ut
overranging.
EXAMPLE: Measuring an unknown re-
sistance
Let’s assume the multimeter is con-
nected to an engine coolant sensor with
unknown resistance. (See Fig. 3)
Fig. 2
Fig. 1
Let’s assume the multimeter is con-
nected to the battery and set to the 20V
range.
The display reads 12.56. This means
there is 12.56V across the battery termi-
nals.
Fig. 3
Start by setting the multimeter to the
largest OHM range. The display reads
0.0Ω or a short circuit.
This sensor can’t be shorted so reduce
the range setting until you get a value of
resistance.
At the 200KΩ range the multimeter mea-
sured a value of 4.0. This means there is
4KΩ of resistance acr
oss the engine
coolant sensor terminals. (See Fig. 4)
If we change the multimeter to the 20KΩ
range (See Fig. 5) the display shows a
Red
Black
Red
Black
Black
Red
oL
600
600
600
600
600
600
®
®
®
To Next Page
Loading...
Need help?
General
