A multimeter measures the voltage and current being exerted through an electrical current. Multimeters test anything that provides electrical continuity. The positive and negative probes tap into an electrical current and provide the measured value of voltage on the display screen. Calibrate multimeters regularly to ensure that it's reading the correct measurement of voltage. The display screen should read .000 when properly calibrated.
Turn the dial located on the face of the multimeter to the "OHM" position. Select the highest OHM setting available.
Touch the metal tips of the positive (Red) and negative (Black) multimeter probes together.
Read the voltage measurement on the display screen. If the multimeter shows .000, the multimeter is calibrated. If the multimeter does not read .000, press the calibration button on the face of the multimeter, while still holding the probes together, until .000 appears on the screen.
Always be careful when dealing with electrical equipment.