Classification of the basis of the purpose or technique
1) Analog computer: analog computer is operate by the measuring the continuously changing physical quantity like pressure temperature and convert them to numeric value
Area of the application: scientific and engineer fields
ii) Digital computer: they are those which operate essential by counting (using information including leers and other symbols in coded from represented by the two state electronic component
Area of the application: general computing automobile aero planes and radar control system
iii) Hybrid computer: combining feature of hybrid and analog computer of them for example, analog computer measures a passion vital sign like pleasure like temperature heart function. This measurement is fees into the digital component that convert them into meaningful information