Which instrument is used to measure DC voltage?

• A. Ammeter
• B. Ohmmeter
• C. Analog voltmeter
• D. Multimeter

Answer: (C)

To measure DC voltage, you need a device that indicates the potential difference between two points without significantly loading the circuit. An analog voltmeter does just that: it is designed with high input resistance so it draws only a tiny current, keeping the circuit behavior essentially unchanged while it measures voltage. Inside, it uses a moving-coil galvanometer with a multiplier resistor to convert the voltage into a deflection on a continuous scale, which makes it well-suited for DC signals where the reading changes smoothly over time.

An ammeter, on the other hand, is meant to measure current and is placed in series in the circuit. An ohmmeter measures resistance by applying a test current or voltage and is used for resistive measurements when the circuit is not energized. A multimeter can measure DC voltage as well, but it is a general-purpose instrument; the analog voltmeter is the traditional device specifically designed for indicating DC voltage with a continuous analog readout.