An introduction to scanner and plotter.


A Scanner is an input device because it takes data such as documents or picture . It converts paper documents, photograph into an electronic format for input to a computer. It is only able to send information into electronic format to the computer and cannot receive information from computer like printer(an output device). It creates a electronic version of the document that can be viewed and edited on computer.

This input device is very useful for preserving paper documents in electronic form because a copy of a document stored in a computer in this manner does not deteriorate in quality with age and can be displayed or printed whenever desired.


  • Flatbed scanner: A flatbed scanner is like a copier machine consisting of a box having a glass plate on its top and a lid that covers a glass plate. To scan a document, a user has to place it upside down on the glass plate. A light below the glass plate moves horizontally from one end to another when activated. After scanning one line, the light beams moves up a little and scans the next line. The process repeats until the beam finishes scanning the entire document. 

  • Hand-held scanner: A user can hold a hand-held scanner in hand easily. It has a set of light emitting diode encased in a small case. To scan a document, a user drag it slowly over the document from one end to another end with its light on. The user must drag the scanner steadily and carefully for correct conversion of document into its equivalent bit map. They are much cheaper than flatbed scanner.


A Plotter is a output device much like a printer. It is used to produce highly precise and good quality of  graphics and drawing under control of the computer . It converts computer output into a graphic, hard copy form. 

It uses ink pen or inkjet to draw graphics or drawings. Either single color or multicolored pens can be employed.

Plotters are widely used to print designs of things such as cars, ships and buildings on a piece of paper using a pen. It is commonly used by architects ,engineers or others who needs precise and good quality of graphics output hard copy. It is also known as graph plotter and more expensive  in comparison to printer.

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Tags:Scanner, Uses of Scanner, input device, Types of scanner, Hand held scanner, Flat-bed scanner, Uses of plotter, Graph plotter, Output device

1 comment:

  1. Thanks for Extraodinary information about Computer networking and telecommunication. It helped me a lot in passing my exams


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