How to Use Multimeters

This guide explains how to use multimeters for performing continuity and voltage checks.

A multimeter, also known as a VOM (volt-ohm-milliammeter), is an electronic measuring instrument that combines several functions, such as measuring voltage, current, and resistance.

See also

This tutorial provides a general overview of multimeters.

Attention

Always turn off the multimeter by setting the dial to OFF after completing your checks.

Fig. 2 A multimeter used for electronics measurements

Continuity Check

In electronics, a continuity check tests whether two points in a circuit are electrically connected. Zero resistance between two points indicates a short, which can be hazardous as it may cause excessive current flow, potentially damaging the circuit.

Note

Multimeter models may differ slightly, but the general instructions are similar.

Performing a continuity check is a safe method for identifying shorts without requiring a power source connected to the circuit.

Steps for a Continuity Check

1. Select the Continuity Function

   • Turn the multimeter dial to the continuity test position. Press the "FUNC." button to enable continuity test mode (indicated by a sound wave icon).

   Continuity test dial position	Continuity test mode

   • Test the mode by touching the multimeter leads together. A continuous beep confirms the mode is active.

     

     Fig. 3 Multimeter leads touching together to test continuity mode

2. Perform the Continuity Check

   • Place the leads on two points of the circuit to test.

     

     Fig. 4 Multimeter leads testing a circuit on a breadboard

   • If the path is continuous, the screen will display a near-zero value, and the multimeter will emit a continuous beep.

   Note

   Ignore short beeps followed by silence; they are not indicative of a short.

General Continuity Check Strategy

• Check all positive (+) terminals to ensure continuity between pairs.

• Check all negative (-) terminals for continuity between pairs.

• Verify that positive (+) terminals are not continuous with negative (-) terminals.

See also

Watch this continuity check tutorial for a visual guide.

DC Voltage Check

1. Select the DC Voltage Mode
   Set the multimeter dial to DC voltage mode (indicated by V with a straight line -V or the symbol ⎓).

   

   Fig. 5 Multimeter dial set to DC voltage mode

2. Perform the Voltage Check

   • Place the positive (red) lead on a positive (+) terminal and the negative (black) lead on a negative (-) terminal.

   • Observe the voltage measurement displayed on the screen.

Note

Reversing the leads (red on - and black on +) will result in a negative reading but will not cause harm.

See also

For a review of circuit basics and Ohm’s Law (\(V = IR\)), check out this SparkFun article.