A voltmeter is an instrument uised for meisurin electrical potential difference atween twa pynts in an electric circuit. Analog voltmeters muive a pointer across a scale in proportion tae the voltage o the circuit; digital voltmeters gie a numerical display o voltage bi uise o an analog tae digital converter.
A voltmeter in a circuit diagram is represented bi the letter V in a circle.
Voltmeters are made in a wide range o styles. Instruments permanently mounted in a panel are uised tae monitor electric generators or ither fixed apparatus. Portable instruments, uisually equipped tae an aa meisur current an resistance in the form o a multimeter, are standard test instruments uised in electrical an electronics work. Ony measurement that can be converted tae a voltage can be displayed on a meter that is suitably calibrated; for ensaumple, pressure, temperature, flow or level in a chemical process plant.
General purpose analog voltmeters mey hae an accuracy o a few percent o full scale, an are uised wi voltages frae a fraction o a volt tae several thoosand volts. Digital meters can be made wi heich accuracy, teepically better than 1%. Specially calibrated test instruments hae higher accuracies, wi laboratory instruments capable o meisurin tae accuracies o a few pairts per million. Meters uisin amplifiers can meisur tiny voltages o microvolts or less.