Which instrument measures resistance?

• A. Amp Meter
• B. Volt Meter
• C. Ohm Meter
• D. Blueprint/Schematic

Answer: (C)

Resistance is a property that tells how much a component opposes current. The instrument that gives this value directly is an ohmmeter. An ohmmeter is designed to apply a small, known test current through the component and measure the voltage across it, or vice versa, then calculate resistance using Ohm's law (R = V/I) and display the result. To obtain an accurate reading, ensure the circuit is de-energized and the component is isolated from other paths, because power in the circuit or parallel/series connections can skew the reading. The other instruments measure different electrical quantities: an ammeter measures current in amperes, a voltmeter measures voltage, and a blueprint/schematic is not a measuring instrument.