Input devices

Input devices are used to input data, information’s and instructions into the RAM. We may classify these devices in following two broad categories.

      1.     BASIC INPUT DEVICES: -     The input devices which have now a day become essential to operate a PC may be called as Basic Input Devices.

a.    KEYBOARD: -     It is similar to a typewriter. It is the main input device of a computer. There is several type of keyboard but 101 key keyboards are much popular. 

b.   MOUSE: -     It is another important input device. It is a pointing device used to move cursor, draw sketches/diagrams, selecting a text/object/menu item on monitor screen while working. The mouse was invented by Douglas Engelbart of Stanford research centre in 1963 and Pioneered by Xerox in 1970s.

      2.     SPECIAL INPUT DEVICES

a.     TRACK BALL: -     A track ball look like a mouse lying on its back as the roller is on the top with selection button on the side. It is also a pointing device used to move the cursor in a particular direction by spinning the ball in that direction

b.    LIGHT PEN: -      It is a pointing device, which is used to select a displayed menu item or draw picture on the monitor screen.

c.     TOUCH SCREEN: -      The screen is sensitive to human figure and act as tactile input device. In touch screen the user can point to a section on the screen instead of pressing any keys.

d.    JOYSTICK: -     Joystick is also a pointing device, which is used to move cursor position on a monitor screen. Joystick is a stick having a spherical ball at its both upper and lower ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions.

e.     SCANNER: -    It is widely used in desktop publishing (DTP) application it is used for digitizing image such as photos, form, documents, etc into computer memory.

f.       Optical Mark Reader/Recognition: -     It is a special type of optical reader used to recognize the type of mark made by pen or pencil. It is used where one out of few alternatives is to be selected and marked. It is specially used for checking the answer sheet of examination having MCQ.

g.     BARCODE READER: -       It is an optical scanner used for reading bar code data. The bar code readers read the bar code data and convert it into electrical pulse, which are then processed by the computer. 

h.    MICR: -      MICR stands for Magnetic Ink Character Reader/Recognition. It is used to recognize the magnetically charged character, mainly found on bank cheque.     

i.       DIGITIZER: -      Digitizer is an input device that is used to enter drawing and sketches into a computer by first converting (digitizing) into digital form.

j.       VOICE INPUT DEVICE: -      Voice input device are latest input device that can recognize the known voice. They seen to be very useful but are not popular due to storage of limited vocabularies and variation in the way of pronouncing words by different people.

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