Analog computer

An analog computer is a device that performs operations on data that are represented within the device by continuous variables having a physical resemblance to the quantities being represented.

The earliest analog computers were constructed with purely mechanical components, such as levers, cogs, cams, discs, and gears. These components represented the quantities being manipulated or the operator-inserted values. Modern analog computers usually employ electrical parameters, such as voltages, resistances, or currents to represent the quantities being manipulated.