MAINTENANCE OF THE M113 PER CARRIER - OD1601 LESSON 2/TASK 2
determine if a continuous electrical flow of the proper value passes through the
circuit or device being tested. The circuit or device is connected between the two
test points, and the multimeter indicates, on a calibrated scale, voltage or ohms
of resistance in the tested circuit or device.
All electrical circuits have some resistance.
Resistances may be so low, or so
high, that they cannot be read with an ordinary multimeter.
A multimeter with a
full-scale reading of about 10 is best for measuring low resistances. High range
multimeters are best for testing insulation leaks. If the normal resistance of the
circuit to be tested is known, select a multimeter with a fullscale range higher
than the normal resistance, which will place the normal reading in the lower two
thirds of the scale.
The following section is intended only as a brief review of multimeter use. Shop
test sets may contain any one of three multimeters:
the Simpson 160 shown in
figure 11 (on the following page), the TS-352 B/U shown in figure 12 (on page 35),
or the AN/URM-105 shown in figure 13 (on page 36).
Any of these can be used in
troubleshooting the vehicle.
The multimeter must be zeroed before it is used to
perform any tests on the vehicle.
(a) Zeroing the Multimeter.
The multimeter must be zeroed mechanically and
electrically before using it to perform tests.
1 Mechanically Zeroing the Multimeter.
The multimeter must be
mechanically zeroed before any tests are performed.
The mechanical zeroing
procedures are the same for all three types of multimeters.
a Place the meter in the position in which it will be used, either
upright or lying down.
b Be sure that the probes are separated and not connected to a circuit.
c Insert a screwdriver in the adjustment screw slot and adjust the meter
until the needle is over the zero at the left end of the scale.
33
Previous Page
