What device is used to measure voltage in an electrical circuit?

The device used to measure voltage in an electrical circuit is the voltmeter. A voltmeter is specifically designed to measure the potential difference, or voltage, between two points in an electrical circuit. It is connected in parallel to the component whose voltage is being measured. The voltmeter displays the voltage levels, allowing for the assessment of how much electrical potential energy is available to drive current through the circuit.

In contrast, an ohmmeter measures resistance (measured in ohms) within a circuit, thereby not providing information about voltage. An ammeter measures the current flow (in amperes) in a circuit and is connected in series with the components. Lastly, a power meter measures the total power (in watts) consumed by the circuit, blending voltage and current into one measurement, but does not directly measure voltage by itself. Thus, the voltmeter is uniquely suited for the task of measuring voltage alone.