Volmeters are electronic devices that are used to measure the voltage in a circuit. There are several synonymous terms used for voltmeters, including voltage meters and electrometers. These instruments are widely used in electrical engineering, physics, and electronics applications. Ammeters, on the other hand, are used to measure the electrical current in a circuit. Other terms for ammeters may include current meters or amp meters. Both ammeters and voltmeters play a vital role in measuring the electrical properties and characteristics of a circuit. With the advancement of technology, digital voltmeters and ammeters have become popular, offering greater precision and accuracy in reading electrical measurements.