What tool is used to measure voltage?

The tool used to measure voltage is a voltmeter. This device is specifically designed to measure the electrical potential difference between two points in an electric circuit. A voltmeter typically has high resistance so that it does not significantly alter the current flowing in the circuit when connected. It provides readings in volts and is essential for diagnosing and troubleshooting electrical systems, as understanding the voltage levels is crucial in ensuring proper functionality and safety.

Other tools mentioned serve different purposes: an ammeter measures current (in amps), an ohmmeter measures resistance (in ohms), and a wattmeter measures power (in watts). Each of these tools serves a unique role in measuring electrical parameters, but only the voltmeter is suited for measuring voltage directly.