Dial (measurement)

A dial is generally a flat surface, circular or rectangular, with numbers or similar markings on it, used for displaying the setting or output of a timepiece, radio, clock, watch, or measuring instrument.

[1] Many scientific and industrial instruments use dials with pointers to indicate physical properties.

Examples include pressure and vacuum gauges,[2] fluid-level gauges (for fuel, engine oil, and so on), voltmeters and ammeters, thermometers and hygrometers, speedometers and tachometers, and indicators (distance amplifying instruments).

Traditionally these have been mechanical devices, but with the advent of electronic displays,[3] analog dials are often simulated from digital measurements.

They usually consist of a small mirrored strip running parallel to the graduations of the scale under the pointer.