A mechanism which displays a continuing indication of the performance of the machine it serves.
An old-fashioned alarm clock is an example. Movement of the gears inside the clock produces an observable, continuing forward movement of the clock’s hands.
In motor fuel marketing, one of the most common usages of the term analog has to do with service station dispensers. In a mechanical dispenser, the movement of gasoline or other liquid fuel through the meter causes pistons to rotate a meter output shaft. As the shaft rotates, it moves a series of wheels on which are embossed numbers, numbers representing gallons dispensed and price values. These numbers are displayed in little windows on the face of the dispenser.
The National Conference on Weights and Measures refers to meters of this type, in mechanical dispensers, as analog devices.
Electronic dispenser meters, in which the price and gallonage figures are displayed in the form of electronically controlled numbers, are referred to as digital devices. In digital devices, the changing display of numbers is not continuous. Instead the numbers change in what are referred to as “discrete” or separate steps. A number is displayed and then, instead of gradually changing, it is instantly replaced by a succeeding number.
See also Digital.