What is a voltmeter used for?

A voltmeter is specifically designed to measure the electrical potential difference, or voltage, between two points in a circuit. It provides a representation of how much electrical energy is available to drive an electric current between those points. This measurement is crucial for understanding how much electrical force is motivating the current flow, helping technicians diagnose and analyze electrical systems effectively.

When a voltmeter is connected across components in a circuit, it does not interfere with the operation of the circuit as it has a high internal resistance. This ensures that it draws minimal current, allowing the circuit to function normally while providing an accurate voltage reading. This characteristic is essential for obtaining reliable measurements in various applications, from troubleshooting to circuit design.

Other options refer to different tools or functions: measuring electrical current requires an ammeter, measuring resistance involves a different method often using an ohmmeter, and converting AC voltage to DC voltage would typically involve rectifiers or other circuitry rather than a measuring device.