Based on the principles of operation, computers are classified into three types, analog computers, digital computers and hybrid computers. Computers
Analog Computers Analog Computer is a computing device that works on continuous range of values. The analog computers give approximate results since they deal with quantities that vary continuously. It generally deals with physical variables such as voltage, pressure, temperature, speed, etc.
Digital Computers On the other hand a digital computer operates on digital data such as numbers. It uses binary number system in which there are only two digits 0 and 1. Each one is called a bit. The digital computer is designed using digital circuits in which there are two levels for an input or output signal. These two levels are known as logic 0 and logic 1. Digital Computers can give the results with more accuracy and at a faster rate. Since many complex problems in engineering and technology are solved by the application of numerical methods, the electronic digital computer is very well suited for solving such problems. Hence digital computers have an increasing use in the field of design, research and data processing. Digital computers are made for both general purpose and special purpose. Special purpose computer is one that is built for a specific application. General purpose computers are used for any type of applications. It can store different programs and do the jobs as per the instructions specified on those programs. Most of the computers that we see fall in this category.
Hybrid Computers A hybrid computing system is a combination of desirable features of analog and digital computers. It is mostly used for automatic operations of complicated physical processes and machines. Now-a-days analog-to-digital and digital-to-analog converters are used for transforming the data into suitable form for either type of computation.
For example, in hospital’s automated intensive care unit, analog devices might measure the patients temperature, blood pressure and other vital signs. These measurements which are in analog might then be converted into numbers and supplied to digital components in the system. These components are used to monitor the patient’s vital sign and send signals if any abnormal readings are detected. Hybrid computers are mainly used for specialized tasks.