If the DMM displays OL during voltage measurement, what should you do?

• A. Switch to a lower range
• B. Switch to a higher range
• C. Recalibrate the meter
• D. Replace the battery

Answer: (B)

OL on a voltage measurement means the input signal is higher than what the current range can handle. The fix is to switch to a higher voltage range. Digital meters measure voltage by using a resistor divider to scale the unknown voltage down to the ADC’s workable input. If the voltage is too large for the chosen range, you get an overload reading. By selecting a higher range, the meter widens the maximum it can accept, bringing the signal into range and allowing a numeric reading. After switching, aim for a range just above the expected voltage to get better resolution without risking overload. Also ensure you’re measuring the correct type (DC or AC) and that the probes are connected properly. Recalibration or a fresh battery isn’t the remedy for an overload reading.