A voltmeter, also known as a voltage meter, is an instrument used for measuring the potential difference, or voltage, between two points in an electrical or electronic circuit. Some voltmeters are intended for use in direct current (DC) circuits; others are designed for alternating current (AC) circuits. Specialized voltmeters can measure radio frequency (RF) voltage.
Voltmeters provide a way to safely measure the voltage, or the difference in electric potential, between two points in a circuit while not changing the voltage in that circuit. The capability to measure voltage is critical to designing and maintaining advanced technology, but it also has more common and practical applications.
