• What is Computer

    Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of set of instructions (called program), gives the result (output), and saves it for the future use.

  • Functionalities of a computer

    Takes data as input. Stores the data/instructions in its memory and use them when require Processes the data and converts it into useful information. Generates the output

  • Characteristics of Computer

    1) Automatic 2) High Speed 3) Accuracy 4) Storage Capability 5) Diligence 6) Versatility 7) Reliability 8) Reduction in Paper Work

  • Application of Computer

    1) Business 2) Banking 3) Education 4) Marketing 5) Health Care (Medical) 6) Military (Defense) 7) Entrainment 8) Railway

  • Application of Computer

    1) Business 2) Banking 3) Education 4) Marketing 5) Health Care (Medical) 6) Military (Defense) 7) Entrainment 8) Railway

  • Analog Computer

    An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.

  • Digital Computer

    A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.

  • Hybrid Computer

    A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations.

  • Keyboard

    Keyboard is the most common and very popular input device which helps in inputting data to the computer Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet.

  • Mouse

    Mouse is most popular pointing device to make selection on screen.

  • Joystick

    Joystick is also a pointing device which is used to move cursor position on a monitor screen. The function of joystick is similar to that of a mouse. It is mainly used in Computer Aided Designing(CAD) and playing computer games.

  • Light Pen

    Light pen is a pointing device which is similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen.

  • Track Ball

    Track ball is an input device that is mostly used in notebook or laptop computer, instead of a mouse.

  • Scanner

    Scanner is an input device which works more like a photocopy machine. It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation

  • Digitizer

    Digitizer is an input device which converts analog information into digital form. Digitizer can convert a signal from the television or camera into a series of numbers that could be stored in a computer.

  • Microphone

    Microphone is an input device to input sound that is then stored in digital form. The microphone is used for various applications like adding sound to a multimedia presentation or for mixing music.

  • Optical Character Reader(OCR)

    OCR is an input device used to read a printed text. OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system memory.

  • Bar Code Readers

    Bar Code Reader is a device used for reading bar coded data (data in form of light and dark lines). Bar coded data is generally used in labelling goods, numbering the books etc.

  • Optical Mark Reader(OMR)

    OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked.

  • Monitors

    Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer.

  • Cathode Ray Tube (CRT)

    CRT or Cathode Ray Tube Monitor is the typical monitor that you see on a desktop computer. It looks a lot like a television screen, and works the same way. This type uses a large vacuum tube.

  • Liquid Crystal Displays (LCD)

    This type of monitors are also known as flat panel monitor. Most of these employ liquid crystal displays (LCDs) to render images. These days LCD monitor are very popular.

  • Printers

    Printer is an output device, which is used to print information on paper There are two types of printers a) Impact Printers b) Non-Impact Printers

  • Impact Printers

    The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.

  • Characteristics of Impact Printer

    Very low consumable costs Very noisy Useful for bulk printing due to low cost There is physical contact with the paper to produce an image

  • Non-impact Printers

    Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers.

  • Plotter

    A plotter is a special kind of output device that, like a printer, produces images on paper, but does so in a different way. Plotters are designed to produce large drawings or images.

  • Speaker

    Speakers are another type of output device, which allow you to listen to voice like music, and conversation with people.

  • Projector

    A projector is a device that uses light and lenses to take an image and project a magnified image onto a larger screen or wall.

  • CPU –Central Processing Unit

    CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results and instructions(program). It controls the operation of all parts of computer.

  • Cache Memory

    Cache memory is a very high speed semiconductor memory which can speed up CPU. It acts as a buffer between the CPU and main memory. It is used to hold those parts of data and program which are most frequently used by CPU

  • Primary Memory (Main Memory)

    Primary memory holds only those data and instructions on which computer is currently working. It has limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device.

  • Random Access Memory

    RAM(Random Access Memory) is the internal memory of the CPU for storing data, program and program result. It is read/write memory which stores data until the machine is working.

  • Read Only Memory

    ROM stands for Read Only Memory. The memory from which we can only read but cannot write on it. This type of memory is non-volatile. The information is stored permanently in such memories during manufacture

  • Types of ROM

    PROM (Programmable Read only Memory) EPROM(Erasable and Programmable Read Only Memory) EEPROM(Electrically Erasable and Programmable Read Only Memory)

  • What is Software

    Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem.

  • what is System Software

    The system software is collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software serves as the interface between hardware and the end users.

  • What is Application Software

    Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software.


    is a computer program that has capability of self extracting to itself. It is a small block of codes that obtain the control of a PC’s, CPU and direct to perform unusual & often distractive actions.