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Tuesday, August 7, 2018

What Is Input And Output Devices Of Computer With Example?


Peripheral devices are devices connected to the computer externally.If a peripheral devices is disconnected, the computer will still be able to  work ; only functoins perfomoed by this peripheral device will not be available.
Mainly there are following type of peripheral device:

  1. Input Devices
  2. Output Devices

Input devices accept data and instructions from the user.Following are the examples of various input devices ,which are connected to the computer to provide input.There are many input devices.Some important input devicesare as following:
  1. Keyboard
  2. Mouse
  3. Joystick
  4. Lightpen


A keyboard (as shown in figure 3)is the most common input device now.Serveral kinds of Keyboard are available , but they resemble each other with minor variations.The Keyboard in most common use is the QWERTY board (from keys Q,W,E,R,T,Y in the top left corner of the keyboard).IBM and IBM compatible PCs or microcomputers use 104 keyboard; so called , since it has 104 keys.In these keyboards the cursor control keys are duplicated to allow easier use of the numeric pad.


A mouse is an electro-mechanical, hand-held device(as shown in figure 4).It is used as a pointer.It can perform functions like select menu commands,move icons,resize windows,start programs,and choose options.
The most common mouse uses an internal, meganetically coated ball, to delect the movement of the mouse acrss a flat surface, usually a desktop. All windows based application today are desgned to work with a mouse.A mouse is used to replace hard to remember key combinations with easier”Point and click” actions.However,It cannot substitule all keyboard operations.Its can be alternative for commonds based opreations.


It has a rubber or metal hall on its underside that can roll in all directions.Mechnically sensors with in the mouse delect the direction in witch the ball is rolling and move the screen pointer accordingly.

It is same as mechanical mouse,but uses optical but uses optical sensor to delect the motion of the ball.

3.Optical or Laser:
It uses a laser to delect the mouses movement.Optical mouse has no mechanical moving parts,they respond more quickly and precisely than mechanical and optomechanical mouse but they are also more expensive.

A joystick Is a pointing devices. It is basically a lever that moves In all directions and controls the movement of a pointer. A joystick is similar to a mouse ,except that with a mouse the cursor stops moving as soon as you stop moving the mouse, with a joystick the pointer continues moving in the direction the joystick is pointing. To stop the pointer you must return the joystick to its upright position.Most joysticks include two button called triggers.
Joystick are used mostly for computer gemes,but they are also used occasionally for CAD/CAM systems and other applications.It provides more realistic control than a mouse or a keyboard for many gemes(e.g,flight simulators).The joystick is attached to the computer through a cable connected to the “gemes port”.Most computers come with one game port.joystick are not used for business applicatons such as word-proessing , data analysis (using spreadsheet) or data management.

An input device that utilizes a light – sensitive detector to select objects on a display screen.A light pen is similar to a mouse , except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.
2.Output Devices
Output devices return processed data that is information , back to the user.some of the commonly used output devices are:
  1. Monitor
  2. Pinters
  3. Plotter
  4. Speakers

Out of all the output devices,monitor is perhaps the most important,because it is the output device that people interact with most intensively.
Computer information is displayed, visually with a video adapter card and monitor  information processed with in the CPU that needs to be visually displayed,is sent to video adapter.The video adapter converts information sent to it by a cable service.
Two basic types of monitors are used with microcomputer, which are as follows:
  • CRT
  • LCD

Either of these types can be Monochrome displaying one colour against a contrasting background (often black) or displaying all colour.
When people talk about the capabilities of various monitors, one critical statistic is the resoluation of the monitor.Today most monitors have a resolution of at least 800×600 pixels.High-end monitors can have resolutions of 1024×768 pixels or even 1280×1024 pixels.Thus both monochrome and coloured monitors are available either in low resolution or in high resoluation.


After a document is created on the computer, it can be sent to a printer for a printer for a hard copy (printout).Some printers offer special features such as coloured and large page formats.Some of the commonly used printers are:
  1. Laser Printer
  2. Dot Matrix Printer
  3. Ink jet Printer
  4. Line Printer

1.Laser Printer
A laser printer produces high quality print that one normally finus in publishing.It is extremely fast and quiet.Moreover the operation of a laser printer is extremely easy with automatic paper loading and no smudging or messing up of ink ribbons.Most laser printers output 6 to 12 pages per minute.Minimum buffer memory in a laser printer is 1MB.

2.Line Printer
A line printer is generally used with large computer systems to produce text based data processing reports.Line printers are high-speed printers with speeds ranging anywhere from 100 to about 3800 lines per minute.In the past,print quality on line printers was not high. Developments in technology are improving the print quality on line printers.These are in the cost range of lacs.


A plotter is a special kind of output device that like a printer, produces images on paper but does so in a different way. Plotter are designed to produce large drawings images , such as construction plans for buildings or blueprints for for mechanical objects.A plotter can be connected to the port normally used by a printer.
An array of different coloured pens in a clip rack and a robotic arm is part of plotter.The instructions that a plotter receives from a computer consist of a colour and beginning and ending coordinates for a line.With that information the plotter picks up the appropriate pen through its arm , positions it at the beginning coordinates, drops the pen down to the surface of the paper and draws to the surface of the paper and draws to the ending coordintes.Plotters draw curves by creating a sequence of very short straight lines.


Speakers are output device,which allow you to voice like music even conversation with people.

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