By Timothy Boyer, Updated Mar 24, 2022
Accurately measuring volts DC (VDC) is essential for diagnosing, troubleshooting, and validating electronic circuits. Voltage drives electrons through a circuit, and knowing its value at key points ensures that components function within their specified limits.
Attach the black probe to the COM (common) terminal on your digital multimeter.
Attach the red probe to the VΩmA (voltage/ohm/milliamp) terminal on the meter.
Turn the selector dial to the 20‑volt range. Most meters offer ranges such as 200 mV, 2 V, 20 V, 200 V, and 600 V. Selecting a range too low will typically display “1”, while a range too high shows only an integer value with no decimals.
Touch the black lead to the negative (-) terminal of a 9‑V battery.
Touch the red lead to the positive (+) terminal of the same battery.
The meter will show a voltage slightly below 9 V. A new 9‑V battery typically measures between 7.2 V and 9 V. This value reflects the battery’s current voltage output rather than its remaining capacity; modern batteries deliver near‑full voltage until they are fully depleted.
Negative readings indicate reversed leads—swap them to get a positive value. To measure voltage in a circuit, place the leads either parallel to the path or on opposite sides of a component.
Never insert meter leads in series with a circuit when measuring voltage. This practice is correct for current measurement but can damage the meter and create safety hazards.
