On the basis of Activity

On the basis of the activities performed, computers may be classified into :
i.. Analog Computer
ii..Digital Computer
iii..Hybrid Computer
i.Analog Computer :
        The computer which can process analog quantities(continuous data) is called an Analog computer.They are designed to accept physical forces such as temperature,pressure,speed of rotation etc and record them as readings along a continuous scale.
Examples of Analog devices are:
Thermometer   :   Which is used to measure the temperature of our body.
Speedometer   :   Which is used in cars to measure their speed.

ii.Digital Computer :
   The computer which accepts discrete data (discontinuous data) is known as digital computer.Basically, digital computer counts digits which represents numbers or letters.They are the most widely used type of computers.They are used in preparation of reports, results, tabulation, graphics, etc in business,accounting ,engineering and other fields.
Examples of Digital Computers are :
IBM-PC (International Business Machine-Personal Computer)
IBM Compatibles
 
iii Hybrid Computer :
    The data processing device which use both analog and discrete data representation is known as hybrid computer.Hybrid computer can perform the tasks of both analog and digital computers as well.They can transfer data from analog to digital and vice-versa.They are also used in scientific research, industrial application aeroplanes etc.