6 input output devices

input output devices

1. I/O Devices
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2. Input Devices
•Touch Screen
•OMR
•OBR
•OCR
•Light Pen
•Scanner
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3. Touch Screen
•A touch screen is a computer display screen that is also an input
device. The screens are sensitive to pressure; a user interacts with the
computer by touching pictures or words on the screen.
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4. OMR
•OMRisaspecialtypeofopticalscannerusedtorecognizethetypeof
markmadebypenorpencil.Itisusedwhereoneoutofafew
alternativesistobeselectedandmarked.
•Itisspeciallyusedforcheckingtheanswersheetsofexaminations
havingmultiplechoicequestions.
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5. OBR
•BarCodeReaderisadeviceusedforreadingbarcodeddata(dataintheformof
lightanddarklines).Barcodeddataisgenerallyusedinlabellinggoods,
numberingthebooks,etc.Itmaybeahandheldscannerormaybeembeddedin
astationaryscanner.
•BarCodeReaderscansabarcodeimage,convertsitintoanalphanumericvalue,
whichisthenfedtothecomputerthatthebarcodereaderisconnectedto.
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6. OCR
•OCRisaninputdeviceusedtoreadaprintedtext.
•OCRscansthetextoptically,characterbycharacter,convertsthem
intoamachinereadablecode,andstoresthetextonthesystem
memory.
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7. Light Pen
•Lightpenisapointingdevicesimilartoapen.Itisusedtoselectadisplayed
menuitemordrawpicturesonthemonitorscreen.Itconsistsofaphotocelland
anopticalsystemplacedinasmalltube.
•Whenthetipofalightpenismovedoverthemonitorscreenandthepenbutton
ispressed,itsphotocellsensingelementdetectsthescreenlocationandsends
thecorrespondingsignaltotheCPU.
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8. Scanner
•Scannerisaninputdevice,whichworksmorelikeaphotocopymachine.Itisused
whensomeinformationisavailableonpaperanditistobetransferredtothe
harddiskofthecomputerforfurthermanipulation.
•Scannercapturesimagesfromthesourcewhicharethenconvertedintoadigital
formthatcanbestoredonthedisk.Theseimagescanbeeditedbeforetheyare
printed.
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9. Digitizers
•Digitizerisaninputdevicewhichconvertsanaloginformationintodigitalform.Digitizercan
convertasignalfromthetelevisionorcameraintoaseriesofnumbersthatcouldbestoredina
computer.Theycanbeusedbythecomputertocreateapictureofwhateverthecamerahad
beenpointedat.
•DigitizerisalsoknownasTabletorGraphicsTabletasitconvertsgraphicsandpictorialdatainto
binaryinputs.Agraphictabletasdigitizerisusedforfineworksofdrawingandimage
manipulationapplications.
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10. Output Devices
•Plotters
•LCD Projector
•Plasma Display
•Printers
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11. Plotter
•Aplotteris a computer hardware device much like a printer that is used for
printing vector graphics. Instead of toner,plottersuse a pen, pencil, marker, or
another writing tool to draw multiple, continuous lines onto paper rather than a
series of dots like a traditional printer.
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12. LCD Projector
•AnLCDprojectorisatypeofvideoprojectorfordisplayingvideo,imagesorcomputerdataonascreenor
otherflatsurface.Itisamodernequivalentoftheslideprojectororoverheadprojector.
•Theyarecommonlyusedinbusinessmeetings,presentationsandseminars.
•LCDprojectorsworkbyusingthreeliquidcrystalpanels,alamp,aprism,andfilterstocreatetheimageon
thescreen.FromtheretheLCDpanelssendthelightthroughthedichroicprismwhichrecombinesthelight
andsendsitoutthemainlensintheLCDprojectortothesurfaceagainstwhichitisprojected.
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13. Plasma Display
•Aplasmadisplayisacomputervideodisplayinwhicheachpixelonthescreenis
illuminatedbyatinybitofplasmaorchargedgas,somewhatlikeatinyneon
light.Plasmadisplaysarethinnerthancathoderaytube(CRT)displaysand
brighterthanliquidcrystaldisplays(LCD).
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14. Printers
•Printer is an output device, which is used to print information
on paper.
•There are two types of printers −
•Impact Printers
•Non-Impact Printers
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15. •Impact Printers
•Impact printers print the characters by striking them on the ribbon, which is then pressed on
the paper.
•Characteristics of Impact Printers are the following −
•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
•These printers are of two types −
•Character printers
•Line printers
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16. •Character Printers
•Character printers are the printers which print one character at a time.
•These are further divided into two types:
•Dot Matrix Printer(DMP)
•Daisy Wheel
•Line Printers
•Line printers are the printers which print one line at a time.
•These are of two types −
•Drum Printer
•Chain Printer
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17. •Non-impact Printers
•Non-impact printers print the characters without using the ribbon. These printers print a complete page
at a time, thus they are also called as Page Printers.
•Characteristics of Non-impact Printers
•Faster than impact printers
•They are not noisy
•High quality
•Supports many fonts and different character size
•These printers are of two types −
•Laser Printers
•Inkjet Printers
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