What are Input Devices {Mouse, Keyboard, Scanner , digitizer} it's Types And work.

Hello friends.. in this post. Today we have going to learn that, what is input devices? What are the types of  input devices and how to work they on given by computer command?

On above topics.. we are going to discuss deeply. So, please keep attension and Read carefully.

Input Devices


   The input devices are peripherals devices by means which a user can interact with the computer. with this devices , user has to feed in instructions and data to the computer.    

  • Keyboard 


      Keyboard is the most frequently used input device.a keyboard provides a set of Alphabatic , numeric ,special symbols and control keys .

The keys are of two types based upon their effects .some keys represent printable character that they can be displayed on the screen .remaining keys represent non printable code and this are responsible for some activity or operation.

   When a character key is pressed ,a coded input signal is sent to the computer, which echoes the signal by displaying a character on the screen.

    Keyboard layout is the arrangement of keys on the keyboard. It is like a standard typewriters. The standard and common can be used layout having  104 keys and divided into following groups -

1.Alphabetical keys -A to Z
2. Numeric keys - 0 to 9
3. Numerical keypad -
4.Curser moment keys/Arrows keys -
5.Function keys - F1 to F12
6.Special keys  - Tab ,Ctrl ,Home , ESC etc.

     The operation of keyboard is associated and handled by a device Keyboard Controller. It is tiny chip.The physical action of pressing down the key on keyboard is called keyboard stroke .

There are three basis types of keyboard -

AT keyboard
             Older computer's (XT ,AT ,LPX) used this type of keyboard it has a large AT Connector that plugs into the motherboard .commonly , referred as DIN-5.

ATX Keyboard
       This are newer type of keyboard and has either USB/PS2 connector .

USB Keyboard
         This keyboard has a standard USB plug on it.
Mouse 

     A mouse is a pointing device, which allows the user to move a mouse pointer on the screen , just by moving around on a flat surface .mouse has become a popular or input device after the invention of GUI (Graphical user interface)Applications. Mouse is very convenient tool to feed input which is otherwise very tedius and cumbersome to key in using keyboard.

           A mouse can have one ,two or three buttons .the left most button is the main button used is most of the applications , in some operating environment like windows, Right mouse button used for specific task.although there are several types of mouse are their but three basic designs are -
Mechanical mouse 
               This are traditional type of mouse and it is most widely used .it has a rotating ball on the bottom and is attached with a card to the system unit.as the use move the mouse across a smooth surface , the roller rotates and controls the pointer on the screen .

• Optical mouse 
       It has no moving parts it emits and senses light to be detect mouse moment .This newer type of mouse has some advantages compared to mechanical mouse .it can be used  on any surface and does not require periodic cleaning .

Cordless or Wireless mouse
         It is a battery powered device that typically uses radio waves or infrared light waves to communicate with the system unit .This devices eliminate the mouse card and free up desk space.

Scanner
         Scanners read data or into from a source (written documents,a graphic image or a photograph ) a scanning device reads the data or information and then converts it into the system unit can process it. There are three types of scanning devices - Optical scanner , Barcode reader and character and mark recognition devices .

• Optical scanner

              This scanner copies or reproduces text as well as images .this device record the light and dark areas as well as color of the scanned document. after image has been scanned, it can be displayed, printed on paper and stored for later uses.There are two basic  types of  optical scanner - Flatbed scanner and portable scanner .

  • Flatbed /Flated scanner
-This scanner is like copy machine. The image to be scanned is placed on  glass surface and this scanner records the image from below.

  • Portable scanner 
It is handheld device that slides across the image ,making direct contact optical scanners are powerful tools for variety of end users including graphics and advertising professional lawyers and students use portable scanner as a valuable research to record the information.

Barcode Readers
This scanners are also called as platform scanners ,this are photoelectric scanners that read the barcode or vertical zebra ,striped marks printed on product containers. This bars store the information of manufactural product code and cost.The scanner scans the pattern of bars a sequence if bits corresponding to bar is generated and the information is collected super markets used electronic cash register and a barcode system called the universal product code(UPC).

• Character and mark recognition devices
This are the scanners that are able to recognize special characters and mark. There are three types -

1)MICR-
Magnetic Ink Character Reader this is used by banks to automatically read those unusual numbers on the bottom of cheques. A special purpose machine none as Reader /Sorter reads character made of ink containing magnetized particles.

2) Optical character Recognition
  It uses special preprinted characters that can be read by light source and changed into machine readable code .These are used in the departmental store to read retail price by reflecting light on the printed characters .

3) OMR( Optical mark recognition)
An OMR device senses the presence or absense of mark such as a pencil mark .OMR is often used to score multiple choice test such as aptitude test or competitive exams.

  •    Digitizers
       This devices convert a sketch of figure into a form that can be processed by a computer.Typically, this devices have some type of flat surface and a writing  device .as the user moves  the writing device across the flat surface the digitizing device records the movement as a series of points and sends the information to the computer. Two widely used digitizing devices used are Graphical tablets and digital notebooks .

Graphical Tablets
This uses a special graphics surface or tablet and a special stylus pen like device .the user either directly sketches on the tablets or stress images that have been placed on the tablet graphics are used by artist ,by map makers and by engineers to save mechanical drawings.

Digital notebooks
These use a regular positioned on top of an electronic pad or tablets.using a regular pen ,the user takes notes and creates drawings on the notepad the underlined electronic pad records the movements.students and business people frequently use this device to record class notes or meeting notes .this notes can be latern be processed, edited and used with a word processing program.

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