Voltmeetri

Voltmeetri, commonly called a voltmeter, is an instrument for measuring electrical potential difference, the quantity commonly referred to as voltage. The unit of measurement is the volt (V). The device is used to determine the voltage between two points in an electric circuit, enabling diagnostics, testing, and design validation.

In operation, a voltmeetri is connected in parallel with the circuit element under test. It is designed with a high input impedance to minimize current draw and circuit disturbance. Most modern voltmeetri are digital and display readings on a screen, while earlier models used analog scales.

Types include analog voltmeetri-based devices using moving-coil or moving-iron mechanisms; vacuum tube voltmeters used in the mid-20th century; and digital voltmeetri (DVMs), which convert the input voltage with an analog-to-digital converter. Handheld digital multimeters often include voltmeetri functionality for DC and AC measurements, with options for true RMS measurement for AC signals.

Specifications cover measurement range, accuracy, and input impedance. Common ranges span from millivolts to several hundred volts for handheld devices, while laboratory instruments can measure kilovolts. Accuracy is given as a percentage of reading or of full scale. For AC voltages, true RMS measurement provides accurate results for non-sinusoidal waveforms.

Origin and usage: the voltmeter concept traces to the development of galvanometers and the work of early electrical experimenters; the volt is named for Alessandro Volta. The voltmeetri remains a standard tool in electronics, electrical engineering, and maintenance, used to verify supply voltages, monitor circuits, and troubleshoot faults.