# Evolution of Computers

## Boolean Algebra

Associated, Distributive, and Commutative Law are described below individually : Associated Law: There is no effect of ORing or ANDing operation on the method of variable grouping. (i)(A+B) + C= A+(B+C) (ii) (A.B).C = A.(B.C) Distributive Law: (B+C) = A.B+A.C   Commutative Law: The input signals are transposed without changing the outputs. (i)   A+B=B+A (ii)   A.B=B.A Proof: (i)    A+B=B+A If A+B=B+A If A=1, B=1 then LSH=1+1=1=B+A=RHS If B=0, B=0 then LHS=0+0=B+A=RHS If A=0, B=1 then...

## Logic Gates

The gate is an electronic circuit to receive more than one input and deliver single output. Gates are often called logic circuits because they can be analyzed with Boolean algebra. The computer system is a set of gates. The ALU (Arithmetic Logic Unit) of computer system is responsible for mathematical and logical processing of data and compiler interacts with ALU at the time of logical operations.The gates are applied in main memory, ALU, resisters etc. Logic gates can also be constructed from relays, diode, fluidics and optical...

## Types of Computers

The computer is divided into three broad categories, and a category has its own categories given as below:     On the basis of Work: Digital, Analog and Hybrid Computer:   Sn Digital computer Analog Computer Hybrid Computer 1. Computers that use binary digits to display discrete information is called digital computer. A computer that uses analog signal to display information is called analog computer. A computer that is able to understand binary as well as analog signal to display information is called Hybrid...

## Microprocessor

Microprocessor is a ULSI (Ultra Large Scale Integration) which contains 1 million transistors, which drive everything from computer in the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles. Three basic characteristics differentiate microprocessors: (a) Instruction set: The set of instructions...

## Application of computer

Some of the applications of computers are as follows: (a)   Home: House management, amusement, communication, and data processing are done through computer.       (b)  Education: E-books, multimedia kits for all subjects, recent information for admission, fee structures from different universities through internet. It is very effective tools for on line education. Many universities offers distance education through Internet. The learning materials are packed in CD-ROM with interactive multimedia. The CAL (Computer Aided...

## Characteristics of Computer

The computer is a name of accuracy, name of miracles and name of recent advance technology which has shrunken the world on a palm. The characteristics of computer are:       (a) Efficiency: The computer processed data in nano second which is beyond of human capacity.   (b) Speed: It is with very high processing speed. The computer can process more than 50 million instructions in one second. Now a day, very high speed computers are available with Pentium IV or Pentium v microprocessor chips.   (c) Storage Capacity: It...

## Integrated Circuit (IC)

The integrated circuit is a subject of micro-electronics in which very small components are designed for several purposes. The integrated chip is also studied and designed under micro-electronics. An integrated circuit is one in which circuit components such as transistors, diodes, resistors, capacitors etc. are automatically part of a small semi-conductor chip. Advantages of Integrated Circuit: (a) Increased reliability due to lesser number of connections amongst components. (b)Extremely small in size, lesser weight, low power consumption,...

## Transistors

Transistor was invented in 1948 by John Bardeen, Willium Bradford Shockley, and Walter Houser Brattain of Bell Telephone Laboratories, U.S.A. The term transistor was coined by John R. Pierce, bell Labs engineers. The transistor is a solid state semi-conductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. A transistor transfers a signal from a low resistance to high resistance. The prefix Trans means the signal transfer property of the device while istor classifies it...

## Vacuum Tubes

The vacuum tube was invented by Lee De Forest in 1907 and called Audion, first amplifying vacuum tube or triode of the world. Lee De Forest was born in Council Bluffs, Iowa (USA) ion August 26, 1873. He had obtained Ph.D in Physics in 1899 on the subject “Reflection of Hertzian waves from the Ends of Parallel Wire“. He had joined Western Electric Company in Chicago in dynamo department. He is a formally educated scientist and regarded as “Father of Radio” for contribution in radio electronics. The Vacuum tube was used in...