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. See also "dial indicator".

There are a number of instruments used in scientific and industrial applications that use dials as an indicator of a specific physical property. A 'Dial Indicator' is a specific measurement tool, while a dial can "indicate" a large number of parameters, such as used in gages, meters, and other measuring devices. Typical examples include, pressure and vacuum gages, level gages, volt and current meters.

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

The term may also refer to a movable control knob used to change the settings of the controlled instrument, for example, to change the frequency of the radio, or the desired temperature on a thermostat.

Styles of Dials:

Circular, Vertical, Horizontal. Fixed Pointer with moving scale Fixed Scale with moving dial

Examples of Dial Usage:

Pressure and Vacuum gages Level gages Volt and Current meters Thermometers and Thermostats (Mechanical) Speedometers and Tachometers

Mirror Dials are designed to reduce or eliminate the effect of paralax. They usually consist of a small mirrored strip running parallel to the graduations of the scale under the pointer. When the observer moves his position so that the pointer obscures the pointer's reflection in the mirror, an accurate reading may be taken.