Transcript Unit 1 b. Input Devices

Input Devices
Hardware
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Input devices
There are a huge range of input devices on the market.
These fall into two main groups:
Manual Input and
Automatic Data Capture.
Manual Input include devices such as the keyboard
and mouse, where the user has to put the data in by
hand.
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Automatic Data Capture devices collect the data
automatically and feed it straight into a computer. Some of
them are operated by people, like bar-code scanners, but
some devices just collect data, such as web cams and data
loggers.
Automatic data capture tends to cut down on errors
compared to manual data entry.
It is usually quicker too – imagine
how long the supermarket queue
would be if every number on the barcode had to be typed by hand.
However, they tend to be more
expensive, and so are usually used
when there is a lot of data to capture.
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Input by touch
With thanks to Logitech.
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Input by light
With thanks to Evesham Technology and Worth.
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Other input
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Input devices all around us
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Input devices around us
Input Device
Place Used
Purpose
OMR
Touch screen
Newsagent
Bus stop
Lottery ticket
Plan your journey
Keyboard
OCR
Concept keyboard
MICR
ATM outside bank
Post Office
Burger bar
Bank
Withdraw money
Sorting letters
Price-up orders
Processing cheques
Bar-code reader
CCTV
Supermarket
Street
Finding cost of items
Security in street
Switch
Pelican crossing
Change traffic lights
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Summary
Input devices fall into two main categories: manual
devices and automatic data capture devices.
Data can be input by touch, sound, light, control,
magnetism and electronic means.
Input devices are being used all around us in daily life.
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Output Devices
Hardware
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Output devices
When a computer has finished processing information, the
information needs to be output so that it can be used.
Monitors:
screens or
Visual Display
Units (VDUs)
display the
effects of what
the user is
doing
can vary in size
and resolution.
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Sometimes we just
need to see the
information, on
screen or on
paper, so we use a
monitor or a
printer.
Printers:
produce a paper
copy of the
user’s work: a
‘hard copy’
come in three
main types:
laser, inkjet and
dot matrix. Some
businesses also
use plotters.
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When a computer has finished processing information, the
information needs to be output so that it can be used.
Speakers:
are used to
output sound,
whether music
or voice
vary a lot in
quality.
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Sometimes we
need to hear the
information, so we
use loudspeakers
or headphones.
Headphones:
work in the
same way as
speakers
can be
cordless.
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When a computer has finished processing information, the
information needs to be output so that it can be used.
Sometimes we
want it to control
something, so we
send a signal to a
motor or a switch
that is part of
another device,
like a robotic arm
or a computerized
sewing machine.
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Output devices – visual and printed
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Output devices – control and sound
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Device suitable for purpose
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Device
Benefits
CRT
Cheapest monitor to buy; gives a sharp picture
LCD
Slim screen; Used for laptops and digital display
TFT
Slim screen; quick to refresh because each pixel
has its own transistor
Speakers
Good for loud music; can address a whole room
Headphones
Can listen without disturbing others; good for private
conversation
Laser
Quick and best quality printer; large paper tray
Inkjet
Cheap colour printing; good for printing photos
Dot matrix
Impact printer; good for multi-part forms
Plotter
Large drawing size; clear lines for technical
drawings
Control
Safe in all conditions; good for repetitive tasks
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Summary
There are four kinds of output devices; devices that
produce a visual or printed output, those that produce
an audio output and others that use control as output.
The three main types of monitors at Cathode Ray Tube
(CRT), Liquid Crystal Displays (LCD) and Thin Film
Transistor (TFT).
There are three main types of printers: dot matrix,
inkjet and laser.
Sound devices include speakers and headphones.
Control devices include hydraulics, pneumatics and
motors.
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