Which device is used to measure resistance?

• A. Ammeter
• B. Voltmeter
• C. Ohmmeter
• D. Multimeter

Answer: (C)

Measuring resistance requires a tool that sources a small test signal and measures the response to determine how much a component resists current. An ohmmeter is made for this purpose; it typically injects a tiny current from an internal battery and reads the resulting voltage drop (or, in some designs, the current drawn) to display the resistance in ohms. That direct function makes it the best choice for measuring resistance. A device that measures current (ammeter) or voltage (voltmeter) isn’t designed to give resistance directly. A multimeter can measure resistance as one of its functions, but a dedicated ohmmeter is specifically built for resistance testing. When taking resistance readings, ensure the circuit is de-energized to get an accurate result.