Chapter 4 Output Devices
CSCA0101 Computing Basics
CSCA0101
COMPUTING BASICS
Chapter 4
Output Devices
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CSCA0101 Computing Basics
Output Devices
Topics:
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Output Devices
Examples of Output Device
Printer
Monitor
Speakers
Projector
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CSCA0101 Computing Basics
Output Devices
Output Devices
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Any peripheral that receives or displays output from
a computer.
Computer
hardware
equipment
used
to
communicate the results of data processing carried
out by a computer to the outside world.
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CSCA0101 Computing Basics
Output Devices
Examples of Output Device
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Monitor
Printer
Speakers
Projector
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CSCA0101 Computing Basics
Output Devices
Monitor
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The device which displays computer output.
The monitor displays the video and graphics
information generated by the computer through the
video card.
Monitors are very similar to televisions but usually
display information at a much higher resolution.
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CSCA0101 Computing Basics
Output Devices
Monitor
Monochrome Monitor
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A monochrome monitor is a
type of CRT computer display
which was very common in the
early days of computing, from the
1960s through the 1980s, before
color monitors became popular.
They are still widely used in
applications such as
computerized cash register
systems
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CSCA0101 Computing Basics
Output Devices
Monitor
Monochrome Monitor
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Monochrome monitors actually display two colors,
one for the background and one for the foreground.
The colors can be black and white, green and black,
or amber and black.
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CSCA0101 Computing Basics
Output Devices
Monitor
Color Monitor
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Color monitors can display
anywhere from 16 to over 1
million different colors.
Color monitors are sometimes
called RGB monitors because
they accept three separate
signals -- red, green, and blue.
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CSCA0101 Computing Basics
Output Devices
Types of Monitor
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Cathode Ray Tube (CRT)
Liquid Crystal Display (LCD)
Light-emitting Diode (LED)
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CSCA0101 Computing Basics
Output Devices
Types of Monitor
Cathode Ray Tube (CRT)
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Large
Heavy
Produce heat
Not expensive
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CSCA0101 Computing Basics
Output Devices
Types of Monitor
Liquid Crystal Display (LCD)
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Less space
Lighter
Low power consumption
Expensive
Limited viewing angle
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CSCA0101 Computing Basics
Output Devices
Types of Monitor
Light-emitting Diode (LED)
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Less space
Lighter
Very expensive
Provide higher contrast and
better viewing angles than
LCD monitor
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Screen Size
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The actual amount of screen
space that is available to
display a picture, video or
working space
Desktop screens are usually
14 - 25 inches by diagonal
measurement.
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Aspect Ratio
• The aspect ratio of a display is the fractional
relation of the width of the display area compared to
its height.
• Two common aspect ratio:
– 4:3
– 16:9
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Aspect Ratio
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Display Resolution
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The resolution of a monitor indicates how densely
packed the pixels are.
In general, the more pixels (often expressed in dots
per inch), the sharper the image.
Most modern monitors can display 1024 by 768
pixels, the SVGA standard.
Some high-end models can display 1280 by 1024,
or even 1600 by 1200.
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Display Resolution
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Refresh Rate
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The refresh rate is the number of times in a second
that a monitor draws the data.
The refresh rate for a monitor is measured in hertz
(Hz)
The standard refresh rate is 75Hz, this means that the
monitor redraws the display 75 times per second.
A flickering monitor can contribute to eyestrain and
headaches.
The faster the refresh rate, the less the monitor
flickers.
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Refresh Rate
Monitor flickering
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Color Depth
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Color depth describes how many colors that can be
displayed on a monitor's screen.
• Common color depths used by monitor:
– 4-bit (EGA) = 16 colors
– 8-bit (VGA) = 256 colors
– 16-bit (High Color) = 65,536 colors
– 24-bit (True Color) = 16 million colors
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CSCA0101 Computing Basics
Output Devices
Monitor Features
Color Depth
EGA Monitor
VGA Monitor
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CSCA0101 Computing Basics
Output Devices
Printer
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Printer is an external hardware device responsible
for taking computer data and generating a hard copy
of that data.
Printers are one of the most used peripherals on
computers and are commonly used to print text,
images, and photos.
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CSCA0101 Computing Basics
Output Devices
Types of Printer
Printers can be categorized into:
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Impact Printer
Non-Impact Printer
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CSCA0101 Computing Basics
Output Devices
Impact Printer
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It strikes paper and ribbon together to form a
character, like a typewriter.
Advantages
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Less expensive
Can make multiple
copies with multipart
paper
Disadvantages
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Noisy
Print quality lower in
some types
Poor graphics or
none at all
Slow
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CSCA0101 Computing Basics
Output Devices
Impact Printer
Daisy-wheel
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Similar to a ball-head typewriter, this type of printer
has a plastic or metal wheel on which the shape of
each character stands out in relief.
A hammer presses the wheel against a ribbon,
which in turn makes an ink stain in the shape of the
character on the paper.
Daisy-wheel printers produce letter-quality print but
cannot print graphics.
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CSCA0101 Computing Basics
Output Devices
Impact Printer
Daisy-wheel
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CSCA0101 Computing Basics
Output Devices
Impact Printer
Dot-Matrix
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Creates characters by striking pins against an ink
ribbon.
Each pin makes a dot, and combinations of dots
form characters and illustrations.
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CSCA0101 Computing Basics
Output Devices
Impact Printer
Dot-Matrix
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CSCA0101 Computing Basics
Output Devices
Non-Impact Printer
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It uses ink spray, toner powder or inkless
Advantages
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Quiet
Can handle graphics
and often a wider
variety of fonts than
impact printers
Fast
Disadvantages
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More expensive
Occupies a lot of
space
The cost of
maintaining it is high
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CSCA0101 Computing Basics
Output Devices
Non-Impact Printer
Laser Printer (Toner-based)
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A laser printer rapidly produces
high quality text and graphics.
Laser printers are often used in
corporate, school, and other
environments that require print
jobs to be completed quickly and
in large quantities.
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CSCA0101 Computing Basics
Output Devices
Non-Impact Printer
Multifunction Printer
(Toner-based)
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An MFP is an office machine which
incorporates the functionality of
multiple devices in one.
A typical MFP may act as a
combination of some or all of the
following devices:
– Printer
– Scanner
– Photocopier
– Fax
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CSCA0101 Computing Basics
Output Devices
Non-Impact Printer
Ink-jet Printer
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Inkjet printer operates by propelling
variably-sized droplets of liquid or
molten material (ink) onto almost
any sized page.
They are the most common type of
computer printer used by
consumers.
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CSCA0101 Computing Basics
Output Devices
Non-Impact Printer
Thermal Printer (Inkless)
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Thermal printers work by selectively
heating regions of special heatsensitive paper.
These printers are commonly used
in calculators and fax machines; and
although they are inexpensive and
print relatively fast, they produce low
resolution print jobs.
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CSCA0101 Computing Basics
Output Devices
Printing Speed
The printing speed is measured in:
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cps (characters per second)
lpm (lines per minute)
ppm (pages per minute)
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CSCA0101 Computing Basics
Output Devices
Plotter
• The plotter is a computer printer for printing vector
graphics
• Plotters are used in applications such as computeraided design such as diagrams, layouts, specification
sheets and banners
• The plotter is capable of producing color drawings in
a matter of minutes
• Plotters differ from printers in that they draw lines
using a pen
• Plotters are considerably more expensive than
printers
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CSCA0101 Computing Basics
Output Devices
Plotter
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CSCA0101 Computing Basics
Output Devices
Speakers
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A hardware device connected to a computer's
sound card that outputs sounds generated by the
computer.
Speakers can be used for various sounds meant to
alert the user, as well as music and spoken text
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CSCA0101 Computing Basics
Output Devices
Headphones
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Headphones give sound output
from the computer.
They are similar to speakers,
except they are worn on the
ears so only one person can
hear the output at a time.
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CSCA0101 Computing Basics
Output Devices
Projector
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An output device that can take the display of a
computer screen and project a large version of it
onto a flat surface.
Projectors are often used in meetings and
presentations so that everyone in the room can view
the presentation.
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CSCA0101 Computing Basics
Output Devices
Projector
Types of projector
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Cathode Ray Tube (CRT) projector
Liquid Crystal Display (LCD) projector
Digital Light Processing (DLP) projector
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CSCA0101 Computing Basics
Output Devices
Projector
Cathode Ray Tube (CRT) projector
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In the early days of projectors, CRT
projectors were commonly used.
They utilized three tubes, one for
each of the primary colors.
Due to their large size, low light
output and the frequent need to
converge and align the images
projected from each of the three
tubes, they are no longer commonly
used.
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CSCA0101 Computing Basics
Output Devices
Projector
Cathode Ray Tube (CRT) projector
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Long service life; CRT tubes maintain good
brightness to 10,000 hours.
CRT projectors are both considerably larger and
heavier than comparable LCD and DLP projectors.
CRT projectors require far more time to set up and
adjust than LCD and DLP based projectors.
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CSCA0101 Computing Basics
Output Devices
Projector
Liquid Crystal Display (LCD) projector
• LCD projectors work by utilizing
polarized mirrors that pass and
reflect only certain colors of light.
• This causes each channel of red,
green and blue to be separated and
later re-converged via a prism after
passing through an LCD panel that
controls the intensity and saturation
of each color.
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CSCA0101 Computing Basics
Output Devices
Projector
Liquid Crystal Display (LCD) projector
• An LCD projector can achieve greater brightness at a
lower energy consumption
• Smaller than CRT projectors
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CSCA0101 Computing Basics
Output Devices
Projector
Digital Light Processing (DLP) projector
• DLP projectors can be classified as
one-chip or three-chip.
• One-chip DLP projectors can
produce more than 16 million colors
while three-chip models can produce
more than 35 trillion colors.
• This allows DLP projectors to
reproduce more natural and lifelike
images.
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