on the basis of working principle

Analog Computer
Analog computer represents data as physical quantities such as electrical potential,fluid pressure,or mechanical motion and operates on the data by manipulating the quantities.It is designed to process data in which the variable quantities vary continuosly which translates the relationships between electrical quantities,such as current and voltage, and solving equivalent problems.Because of this feature,analog computers were specially designed in useful situations such as the flight of a space capsule or the changing whether patterns over a certain areas.the accuracy of analog computers is bad;they are limited for three to four figures of exactness alternatively.These are specific purpose computers.
    Although analog computer computer's features are commonly found in such form such as    speedometer,thermometers, and watt hours,but these are devices.They  largely have been made obsolete for general purpose mathematical computations and data storage by digital computer.