Skip to main content

A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.

Voltmeters are made in a wide range of styles. Instruments permanently mounted in a panel are used to monitor generators or other fixed apparatus. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter, are standard test instruments used in electrical and electronics work. Any measurement that can be converted to a voltage can be displayed on a meter that is suitably calibrated; for example, pressure, temperature, flow or level in a chemical process plant.

General purpose analog voltmeters may have an accuracy of a few percent of full scale, and are used with voltages from a fraction of a volt to several thousand volts. Digital meters can be made with high accuracy, typically better than 1%. Specially calibrated test instruments have higher accuracies, with laboratory instruments capable of measuring to accuracies of a few parts per million. Meters using amplifiers can measure tiny voltages of microvolts or less.

Part of the problem of making an accurate voltmeter is that of calibration to check its accuracy. In laboratories, the Weston Cell is used as a standard voltage for precision work. Precision voltage references are available based on electronic circuits.


Articles Title

How to test a car battery

If your car's instrument panel includes an ammeter, it will tell you how well the charging syste...

Testing an alternator and checking output

Testing drive-belt tension Check drive-belt tension by pushing or pulling the belt inwards at th...

Testing a dynamo and checking output

The dynamo is a simple direct-current generator with two output terminals. Connect the positive ...

Checking a starter circuit

Inertia starter An inertia starter has the solenoid mounted elsewhere in the engine compartment,...

Checking the low-tension circuit

The low-tension (LT), or primary-ignition, circuit consists of the battery, ignition switch, cont...

купить аккумулятор Днепропетровск