What is the main use of a voltmeter?

The primary function of a voltmeter is to measure the electrical potential difference, also known as voltage, across two points in an electrical circuit. This measurement is crucial for various applications, such as diagnosing circuit faults, analyzing circuit behavior, and ensuring that components receive the correct voltage for operation.

Voltmeters are designed to connect across components or sections of a circuit without significantly altering the circuit's conditions. They have a high internal resistance to minimize the current drawn while taking a measurement, ensuring that they do not impact the circuit's function. Accurate voltage readings are essential for evaluating whether equipment is operating within its specified voltage range, which can prevent damage and improve performance.

While other instruments serve specific functions—like measuring current, resistance, or checking continuity—those purposes are distinctly separate from the role of a voltmeter in assessing voltage levels, making it a specialized tool for that particular measurement.