a) Analog computer: Analogue computers are the computers that measure physical quantities such as pressure and temperature and convert them to numeric values for different calculation. It operates on continuously varying data i.e. analog computer’s output can vary even if the input is identical. For example, a service station gasoline pump contains an analog processor and analog device that converts fuel flow measurements into quantity and price values. Speedometer in cars is another example of analog computer.
b) Micro computer: A micro computer is a computer with a microprocessor as its CPU. They are cheap, compact and can be easily accommodated on a study table. Now-a-days mostly used computers are microcomputers. It is called Home PC or Personal Computer (PC) because it is a single user computer. It supports many higher level languages, multimedia, graphics, 3D graphics and games. The Internet is popular due to PC and it is available for all income groups. It contains memory in the form of ROM (Read Only Memory) and RAM (Random Access Memory), I/O (input/output) ports, and a bus or system of interconnecting wires, housed in a unit that is usually called a motherboard. IBM, Hewlett Packard, Apple, Compaq are some well known companies which manufacture microcomputers.