Check ______ with an ohmmeter.

• A. Voltage
• B. Current
• C. Resistance
• D. Power

Answer: (C)

An ohmmeter is used to determine resistance in a component or path. It works by injecting a small current from its internal battery and measuring the resulting voltage across the test leads, then calculating resistance (R = V/I). This lets you check whether a resistor is within spec or whether a wire or connection is continuous or open. To get an accurate reading, the circuit must be de-energized and the component isolated from other conductive paths; measuring resistance in a powered circuit can give erroneous results or damage the meter. Since voltage and current are measured with voltmeters and ammeters, and power with a wattmeter, an ohmmeter specifically checks resistance.