By David Somerset Updated Mar 24, 2022
A multimeter is an essential tool for measuring voltage, resistance, and current in electrical circuits. When its readings feel off, a systematic check can confirm whether the device is still reliable or needs replacement. Below is a concise, expert‑approved procedure.
Set the meter to the lowest resistance range (displayed as “Ω”). Touch the red probe to the black probe. The screen should read 0 Ω, confirming that the probes are connected directly and the meter’s internal contacts are intact.
Obtain a resistor with a certified value (e.g., a 500 Ω standard resistor). Set the meter to a range that comfortably covers the resistor’s value—use the 100 Ω setting for a 500 Ω resistor if the meter’s ranges are in tens. Place one probe at each end of the resistor. The displayed value should be within 5 % of the resistor’s labeled value. If the reading is off, try a second resistor to rule out a single anomalous component.
Switch the dial to the voltage setting. Place the red probe on the battery’s positive terminal and the black probe on the negative terminal. The meter should read 9 V (or very close, accounting for battery age). A significant discrepancy indicates a calibration issue or internal fault.
If any of the above tests fail, the multimeter is likely defective and should be replaced. A reliable meter is critical for accurate diagnostics and safety.
If your multimeter shows no readings at all, first inspect the battery compartment or the internal fuse for a blown condition.
