GENERAL INSTRUCTIONS FOR USE OF MULTIMETER

TM55-1730-228-13&P

NOTE

Multimeter is a component of Tool Kits, Automotive Maintenance, Organizational:

Set no.

supplemental (SC4910-95-CL-A73), and set no. 2, supplemental (SC4910-95-CL-A08).

a. Voltmeter. The voltmeter has four meter ranges (2, 5, 10 and 50 volts). Two additional ranges (250 and 1000

volts) are useful in checking electronic equipment. Ranges are selected by the range selector switch.

b. Ohmmeter. The ohmmeter is used for making resistance and continuity checks. The ohmmeter is basically a

voltmeter and internal battery connected in series, so that when the two test leads are connected together, the voltmeter

reads the battery voltage. When a conductive circuit is connected between the test leads, the voltmeter will indicate how

much voltage is being lost (voltage drop) in the circuit. In the case of a length of wire, there will be little or no voltage

drop; for a small coil or a resistor, there may be considerable voltage drop. The amount of voltage drop is directly

related to the resistance (in ohms) of the component being checked.

c. Other Scales Since the multimeter is a general purpose instrument intended primarily for electronic checking.

other scales and ranges are provided. These ranges are not normally used for this type of electrical troubleshooting, and

are beyond the scope of this manual.

3-9. GENERAL INSTRUCTIONS FOR USE OF MULTIMETER

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Before proceeding with electrical troubleshooting procedures, paragraphs 3-10 through 3-13 must be read

and understood by all personnel using the multimeter. Incorrect connections to the multimeter could result

in costly damage to test equipment or vehicle components.

a. Be sure of the check to be made and the procedure to be used. Follow the step-by-step procedure given for

each individual check.

b. Always select a meter range higher than the expected reading. Set the meter for this range before connecting it

into the circuit.

c. Be sure to read the correct row of mer scale figures which correspond to the selected range. The range

selector switch or the binding post marking always shows the right-hand figure of the row to be used. For example, if the

range selector is set for 50 volts, read the row of meter scale figures that ends with 50 on the right-hand end.

d. When checking with an ammeter or ammeter shunt, always connect it in series with circuit to be checked. For

maximum safety, the power should be turned OFF when connecting or disconnecting the ammeter or ammeter shunt.

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