The document discusses various computer input and output devices. It describes keyboards, mice, scanners, digital cameras, microphones, and other common input devices. It also covers monitors as visual output and different types of printers like inkjet, laser, and dot matrix as standard output devices. Plotters and speakers are also briefly mentioned.

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1.Introduction

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Input Devices
• Keyboard.
• Mouse
• Light pen
• Scanner
• Touch screen
• Microphone
• Digital Camera
• TrackBall
• Bar code Reader
• Magnetic Ink Card Reader
• Optical Character Reader
• Optical Mark Reader

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The Keyboard
The most commonly used input device is the
keyboard on which data is entered by manually
keying in or typing certain keys. A keyboard
typically has 104 or 108 keys.

4. The keys on the keyboard are as follows −
1)Typing Keys
These keys include the letter keys (A-Z) and digit keys (09) which generally
give the same layout as that of typewriters.
2)Numeric Keypad
It is used to enter the numeric data or cursor movement. Generally, it consists
of a set of 17 keys that are laid out in the same configuration used by most
adding machines and calculators.
3)Function Keys
The twelve function keys are present on the keyboard which are arranged in a
row at the top of the keyboard. Each function key has a unique meaning
and is used for some specific purpose.
4)Control keys
These keys provide cursor and screen control. It includes four directional arrow
keys. Control keys also include Home, End, Insert, Delete, Page Up, Page
Down, Control(Ctrl), Alternate(Alt), Escape(Esc).
5Special Purpose Keys
Keyboard also contains some special purpose keys such as Enter, Shift, Caps
Lock, Num Lock, Space bar, Tab, and Print Screen.
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Keyboard
• The keyboard allows the computer user to
enter words, numbers, punctuation,
symbols, and special function commands
into the computer’s memory.

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The Mouse
Is a pointing device which is used to control the
movement of a mouse pointer on the screen. It can
perform functions like selecting menu commands,
moving icons, resizing windows, staring programs
and choosing options

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Touch screens
• Often used for
applications with
occasional use, for
example
• Bank ATMs,
• Input can be given
through the computer
screen. Users touch
electronic buttons
displayed on the screen
or they may use light pen

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Light Pen
• A light pen is a small
‘pen-shaped’ and, which
contains light sensors
• A light pen is similar to a
mouse except that with a
light pen. We can move
the pointer and select
objects on the display
screen directly by
pointing to the objects
with the pen

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joystick
The main use of a joystick is to
play computer games by
controlling the way that
something moves on the
screen.

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Microphones - Speech Recognition
•Microphone is an input device, which takes
voice as input. The voice communication is
more error-prone than information through
keyboard
•Special software and a microphone are
required

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Microphones - Speech Recognition

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Digital camera
A digital camera can store many more
pictures than an ordinary camera. Pictures
taken using a digital camera are stored inside
its memory and can be transferred to a
computer by connecting the camera to it.

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Track Ball
• Track Ball is a pointing
device, is a mouse lying
on its back. To move the
pointer, you rotate the ball
with your thumb. There are
usually one to three
buttons next to the ball,
Which you use just like
mouse buttons.

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Scanner
A scanner can be used to input pictures and
text into a computer..

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Bar codes
•A bar code is a set of lines of different thicknesses
that represent a number
•Bar Code Readers are used to input data from bar
codes. Most products in shops have bar codes on
them
•Bar code readers work by shining a beam of light
on the lines that make up the bar code and
detecting the amount of light that is reflected back

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17. Magnetic Ink Card Reader (MICR)
• MICR input device is
generally used in banks as
there are large number of
cheques to be processed
every day. The bank's code
number and cheque number
are printed on the cheques
with a special type of ink that
contains particles of
magnetic material that are
machine readable
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18. Optical Character Reader (OCR)
• OCR is an input device used
to read a printed text. OCR
scans the text optically,
character by character,
converts them into a machine
readable code, and stores the
text on the system memory.
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19. Optical Mark Reader (OMR)
• OMR is a special type of
optical scanner used to
recognize the type of mark
made by pen or pencil. It is
used where one out of a few
alternatives is to be selected
and marked. It is specially
used for checking the
answer sheets of
examinations having
multiple choice questions.
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21. • Monitors, commonly called as Visual Display
Unit (VDU), are the main output device of a computer. It
forms images from tiny dots, called pixels that are
arranged in a rectangular form. The sharpness of the
image depends upon the number of pixels.
• There are two kinds of viewing screen used for monitors.
• Cathode-Ray Tube (CRT)
• Flat-Panel Display
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Monitors

22. Cathode-Ray Tube (CRT) Monitor
• The CRT display is made up of small picture
elements called pixels. The smaller the pixels,
the better the image clarity or resolution.
• Most screens are capable of displaying 80
characters of data horizontally and 25 lines
vertically.
• There are some disadvantages of CRT
• Large in Size
• High power consumption
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23. Flat-Panel Display Monitor
• The flat-panel display refers to a class of video devices
that have reduced volume, weight and power
requirement in comparison to the CRT. You can hang th
• The flat-panel display is divided into two categories em
on walls
• LCD (Liquid-Crystal Device).
• LED (Light-Emitting Diodes).
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Monitors
CRT LCD

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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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Printers
• Dot Matrix Printer
• Dot matrix printing is a type of
computer printing which uses a
print head that moves back-and-
forth, or in an up-and-down
motion, on the page
• Ink Jet Printer
– least expensive, color,
slower with a higher per
page cost than laser printers
• Laser Printer
– More expensive, faster,
lower per page cost than ink
jet,

27. Impact printers
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• 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

28. 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
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29. Dot Matrix Printers
• In the market, one of the
most popular printers is
Dot Matrix Printer. These
printers are popular
because of their ease of
printing and economical
price. Each character
printed is in the form of
pattern of dots and head
consists of a Matrix of
Pins of size (5*7, 7*9, 9*7
or 9*9) which come out to
form a character which is
why it is called Dot Matrix
Printer
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30. Advantages
• Inexpensive
• Widely Used
• Other language characters can
be printed
Disadvantages
• Slow Speed
• Poor Quality
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31. Daisy Wheel
• Head is lying on a wheel and pins
corresponding to characters are like
petals of Daisy (flower) which is why it is
called Daisy Wheel Printer. These
printers are generally used for word-
processing in offices that require a few
letters to be sent here and there with
very nice quality.
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33. 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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34. • Drum Printer
• This printer is like a drum in
shape hence it is called drum
printer
• Drum printers are fast in
speed and can print 300 to
2000 lines per minute.
Advantages
Very high speed
Disadvantages
Very expensive
Characters fonts cannot be
changed
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37. Chain Printers
• In this printer, a chain of
character sets is used,
hence it is called Chain
Printer. A standard
character set may have
48, 64, or 96 characters.
• Advantages
• Character fonts can easily
be changed.
• Different languages can be
used with the same printer.
• Disadvantages
• Noisy
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38. Non-impact Printers
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• 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.
• These printers are of two types −
• Laser Printers
• Inkjet Printers
Characteristics of Non-impact Printers
• Faster than impact printers
• They are not noisy
• High quality
• Supports many fonts and different character size

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Inkjet Laser
Non impact printers
• Inkjet printer, also called a
bubble-jet, makes characters by
inserting dots of ink onto paper
• Letter-quality printouts
• Cost of printer is inexpensive
but ink is costly
• These are non-impact page
printers. They use laser lights
to produce the dots needed to
form the characters to be
printed on a page.
• Color printers available
• Expensive initial costs but
cheaper to operate per page

40. Inkjet printer
• Advantages
• High quality printing
• More reliable
• Disadvantages
• Expensive as the cost per page
is high
• Slow as compared to laser
printer
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41. Laser Printer
• Advantages
• High quality printing
• More reliable
• Disadvantages
• Expensive as the cost per page is high
• Slow as compared to laser printer
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Plotter
• It is a special kind of printer used to print large images
like building plans or other such kind of images
• It is used in engineering, drafting, map making.

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Speakers
• Speakers are another
type of output device,
which allows you to listion
to voice like music, and
conversation with people

45. Different types of speakers vary on
the loudness of sound generated.
Some of the speakers used are:
• Ear phone
• Head phone
• Normal speaker
• Woofer
• Loud speaker
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Summary
• Introduction
• Input Devices
– Keyboard,mouse,joystick,scanners,digital
camera, bar code reader, touch
Sreeen,Speech input device (microphone)
• Output Devices
– Monitor , Speaker, Printers ( different
types),plotters

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