input & output devices by damitha nadeesha wanniarachchi

7/31/2019 Input & Output Devices by Damitha Nadeesha Wanniarachchi

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By Damitha Nadeesha Wanniarachchi


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What is an input device?

The devices used to transferdata from the external

environment to the computersystem.

The ideal input device wouldtake the least amount of time& transfer the data accurately

with very little help from the


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Types of Input Devices


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Input Sub System

InputDevice

Hardware.

Firmware.

Interface

Input port

CPU


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Examples for Input devices

KeyboardEntry Devices

ScanningDevices

Voices InputDevices

PointingDevices

ComputerKeyboard

ScannerOCROMRBarcode

-readers

MICR

Microphone

MouseJoystickTouch

-screenLight pen


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Computer Keyboard

This is used to inputdata & informationdirectly to thecomputer easily and

efficiently.

Its one of the maindevices that used tosend data into the

system. There are two types of

keyboard layouts.

1. QWERTY

2. DWORAK


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Scanner

This is a scanning device.

This is used to scan anhardcopy of a image or

text in order to store it orconvert it to a softcopy.

There are two commontypes of scanners.

1. Flat bedScanners

2. Hand heldScanners


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OCR(Optical CharacterReader)


Translates scanned images ,printed

text into machine embedded text.


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OMR(Optical Mark Reader)


Used to read answers on a form or adocument.

Used to mark answers on a answersheet.


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BCR(Bar Code Reader)

This is a scanningdevice.

Bar code is a set oflines of differentthicknesses thatrepresents simpledata.

BCR is used to readdata that is storedon the barcode.

Almost everyproduct in themarket uses


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MICR(Magnetic Ink CharacterRecognition)


It is used to indentify numbers which

are written in using a magnetic ink. Most commonly used in banks to

process checks.


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Microphone

This is used to input vocal or audiodata into the computer.

This device translates analog signalsinto digital signals.

There are 3 common types.

Crystal Dynamic

Condenser


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Mouse

This translates itsmovement on theDesktop into digital

signals; it causes thecursor on the screen tomove.

This is the most commonpointing device.

There are 4 types ofmice.

o Touch pad

o

Track ball


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Touch screen

This device issensitive totouch; a

selection canbe made from amenu on thescreen by

touching a partof it.

These are

commonly seen


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Light pen

This is a penshapeddevice usedto select a

point on thescreen.

This device is

mainly usedby Designers.


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Output Devices


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What is an Output device?

Output devices are used to obtainsoft copies or hard copies of resultsafter processing.


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Examples for Outputdevices

Computer Monitor

Printer

Graph Plotters Computer Output on Microfiche

Projectors

Speakers


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Computer Monitor

This is also called as the(VDU)Visual Display Unit.

This device helps the userto identify the result after

the processing is done. There are 2 types of

monitors.

CRT(Cathode RayTube)

LCD(Liquid CrystalDisplay)


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Printer

This device is usedto produce directinformation ordata on a hard

copy(print out). There are 4 types.

Dot-matrixPrinters

Ink jetPrinters

Bubble jet

Printers


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Graph Plotter

This device is used toproduce graphical outputon paper or linediagrams.

These are for printingplans, maps, linediagrams & 3dimensional drawings.

There are 2 types.

Pen plotters

Pen-less plotters


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Computer Output onMicrofiche(COM)

COM stands forComputer Output onMicrofiche, which ismuch reduced outputproduced on high

quality film. Microficheis a rectangular sheetof microfilm largeenough to contain anumber of pages of

data typically 30-300.It allows a largeamount of data to bestored in a smallamount of space.


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Projector

This device actjust as thecomputermonitor which

can beconnected to thecomputer. Theoutput of thecomputer can beprojected on to ascreen or a wall.

These are usedwhen outputshould be shown


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Speakers

This device is used to get anaudio output from thecomputer. This converts digital

signals into analogsignals(audio signals).

There are 2 types.

Mono Stereo


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Resources

ICT Classroom in a BookPart 1

GCE O/L(Grade 10 & 11) byChandana De Silva

ICT Note Book

GCE A/L (Grade 12 & 13)


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input & output devices by damitha nadeesha wanniarachchi

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