MULTIMETER USAGE

TM 10-3930-660-24-2

ELECTRICAL GENERAL MAINTENANCE INSTRUCTIONS - CONTINUED

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MULTIMETER USAGE - CONTINUED

CAUTION

Before performing a continuity test, always place battery disconnect switch in OFF position (TM 10-3930-

660-10) and disconnect circuit to be tested. Failure to follow this caution may damage multimeter.

Testing for Shorts. A short (or short circuit) occurs when two circuits that should not be connected have continu-

ity with each other. A short also occurs when a circuit that should not touch ground has continuity with ground.

(1)

Zero multimeter.

(2)

Connect black probe to one pin and red probe to either ground or another pin.

(3)

Observe readout and interpret results as follows:

(a) If readout indicates any numeric value above 0 (zero) but less than the meter's limits, circuits are

shorted or circuit is grounded, if testing to ground.

(b) If readout does not indicate a numeric value or value does not change when connected to circuit(s) in

question, circuits are not shorted.

CAUTION

Before performing a continuity test, always place battery disconnect switch in OFF position (TM 10-3930-

660-10) and disconnect circuit to be tested. Failure to follow this caution may damage multimeter.

Testing for Resistance. Allowable resistance readings depend on circuit being tested. Refer to the particular sec-

tion dealing with that circuit or component for allowable readings.

(1)

Zero multimeter.

(2)

Select OHMS.

(3)

Select lowest VOLTAGE/OHMS range. If test specifies ohms range, select required range.

(4)

Connect black and red probes across circuit to be tested.

(5)

Observe readout and interpret results as circuit resistance.

Voltage Tests

Measuring DC Voltage.

(1)

Set multimeter to ON.

(2)

Select lowest possible DC VOLTAGE range that is still higher than voltage to be measured.

(3)

Connect red probe to positive (+) pin and black probe to negative (-) pin.

(4)

Observe readout and interpret results as DC voltage in circuit being tested.

Measuring DC Voltage Drop.

NOTE

Voltage drop is defined as the amount of voltage loss that occurs through all or part of a circuit due to resis-

tance.

(1)

Set multimeter to ON.

(2)

Select lower possible DC VOLTAGE range that is still higher than voltage to be measured.

(3)

Connect red probe to test location closest to positive (+) side. Connect probe to test location closest to

ground.

(4)

Observe readout and interpret results as DC voltage in circuit being tested.

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