What device is used to measure voltage in a circuit?

The device specifically designed to measure voltage in a circuit is the voltmeter. A voltmeter provides a reading of the electrical potential difference between two points in an electrical circuit, which is essential for understanding how much voltage is available to drive current through various components.

While other devices are capable of measuring electrical parameters, they do not measure voltage directly. An ammeter measures the current flowing through a circuit, providing a reading in amperes. A multimeter can measure voltage, current, and resistance, but it encompasses a wider range of functionalities than a dedicated voltmeter. An ohmmeter specifically measures resistance across a component or circuit, which is unrelated to voltage measurement.

Therefore, the voltmeter is the most appropriate device for directly measuring voltage and is used extensively in electrical testing and diagnostics.