By Samuel Markings, Updated Mar 24, 2022

Electricity flows when electrons travel through conductors. Current measures the electron velocity, while voltage quantifies the electric potential per unit charge. Both parameters are routinely checked during fault testing. Power—how quickly energy is consumed—is expressed in watts (W) and can be derived from voltage (V) and current (A) using a digital multimeter.

Step 1 – Connect the Leads

Attach the supplied probes to the multimeter. Insert the red probe into the positive (V/I) jack and the black probe into the negative (COM) jack.

Step 2 – Measure Voltage

Turn the dial to the DC voltage setting labeled “V”. Touch the probes to the terminals of the component under test. The display will show the voltage in volts. Record the value.

Step 3 – Measure Current

Rotate the dial to the DC current setting marked “I”. Re‑place the probes across the component. The meter will now display the current in amperes. Note this figure.

Step 4 – Calculate Power

Compute power with the equation: P = V × I. Multiply the measured voltage by the measured current to obtain the wattage.

Safety tip: Always ensure the device is powered off before connecting probes, and select an appropriate current range to avoid meter damage.