What is one of the functions of a voltmeter?

A voltmeter is designed primarily to measure the electrical potential difference (voltage) between two points in a circuit. One of its key characteristics is that it is constructed to allow only a very small amount of current to flow through it while taking a measurement. This is essential because allowing more current to flow could potentially alter the circuit’s behavior or cause damage to the voltmeter itself.

This minimal current flow helps ensure that the voltmeter does not significantly affect the circuit's performance or introduce errors in the voltage reading. By having a high internal resistance, the voltmeter maintains the integrity of the circuit under test. In essence, a voltmeter's ability to permit very little amperage to flow through it is a fundamental quality that enables accurate voltage measurements without interfering with the circuit.