What does a voltmeter measure?

A voltmeter measures the electrical potential difference between two points in an electrical circuit. This potential difference, often referred to as voltage, indicates the amount of energy each unit of electric charge would have as it moves between those two points. By measuring this potential difference, the voltmeter provides essential information about how much energy is available to push current through the circuit components.

Understanding voltage is crucial in various scenarios, such as troubleshooting circuits, ensuring that devices receive the correct power levels, and assessing the functionality of electrical systems. Essentially, without knowing the voltage, you cannot ascertain whether a circuit is operating as intended or whether it is safe to connect additional devices.

The other choices involve different electrical measurements that are not the primary function of a voltmeter. Measuring current flow relates to an ammeter, while resistance is measured using an ohmmeter. Power consumption typically requires measuring both voltage and current to determine the level of electrical power being used.