Transcript Chapter 2: Introduction to Microprocessor

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Output Devices
Types of Output Devices
MONITORS
PRINTERS
Impact Printers
Dot Matrix
Daisy Wheel
Line Printers
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An output device receives information from the computer and
translates it from machine language to a form that humans can
read or so that another machine can read the information.
Output that is readable by the user can be categorized into two
categories: hard copy or soft copy.
Hard copy is a relatively permanent form of output that can be
read immediately or stored for later use, such as paper. Printers
are the most common hard copy output devices.
Soft copy is a transient form of output, for example, text on a
screen display. It is lost when the computer is turned off unless
it is saved in the main memory or on a disk
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MONITORS
PRINTERS
PLOTTERS
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Monitor :Monitor is an output device that display information. It can display
text as well as graphic images in color or black & white while based on
monitor type.
Based on color Monochrome: It display two colors, one on the foreground
and one on the background. The colors can be black and white, green and
black or amber and black. Gray-scale: Special type of monochrome monitor
capable of displaying different shades of gray.
Multi-Color: They are called RGB monitors, they accept three separate
signals-Red, Green and Blue. A multi-color monitor can display any color.
Based on signals Digital monitor: It accepts digital signals rather than analog.
The term digital refers to the type of input received from the video adapter.
Digital monitors are fast and produce clear images. Eg: Flat-panel display
which uses Liquid Crystal Display technology.
Analog monitor: This is the traditional type of color display that has
been used for years in televisions. In reality all monitors based on
CRT(Cathode Ray Tube) technology are analog. The monitor
consumes much space.
BACK
 Printer
is the most important
output device,which is used to
print information on paper.
most c
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Printers can be divided into two distinct categories :
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IMPACT PRINTERS: The printers that print the
characters by striking against the ribbon and onto the
paper.In these printers, there is a mechanical
contact between the print head and paper.
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NON IMPACT PRINTERS: The printers that print the
characters without striking against the ribbon and
onto the paper In these printers, there is no
mechanical contact between the print head and
paper.
BACK
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The printers that
print the characters
by striking against
the ribbon and onto
the paper.In these
printers, there is a
mechanical contact
between the print
head and paper.
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Print head contains a
vertical array of pins.
As the print head moves
across the paper, selected
pins fire against the
ribbon.
Each character printed is
in form of pattern of
DOTs.
The more pins the print
head has the better will
be the printing quality.
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The printer look like daisy contains a disk made of
plastic or metal on which letters and symbols are
placed on each patel .
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When printer needs to print a character, it sends the
signal to mechanism called printhead, the printhead
rotates the daisy wheel until the desired letter is in
place and facing the paper.
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Then a electromechanical hammer called Solenoid
strikes the back of the character contained petal,
forcing the character to hit an ink ribbon, leaving an
impression of the character on the paper.
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Daisy wheel printing speed is measured in
character per second and standard speed is 10 to
50 characters per second.
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They are printers of letter quality type.
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It cannot print graphic images. They are noisy and
slow.
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Line Printers are the printers which print one
line at a time.
These are Impact printers for producing very
large volume paper output.
Speed is 300 to 3000 lines per minute.
The most commonly used printers in this
category are
 WHEEL PRINTER
 DRUM PRINTER
 CHAIN PRINTER
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It has characters fixed in type assembled on a
chain.
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With the rotation of band, hammer is activated
when desired character comes in front of it.
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Speed varies from 400 to 3000 lines per minute.
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The Wheel printer has 120 rotating wheels.
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There are 48 characters on each wheel.
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At the time of printing , all the 120 print
wheels are positioned for the data to be
printed.
In this case , complete line of 120 characters
is printed at one line.
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It consist of cylindrical drum on which characters are
embossed for each & every print position on line.
Drum is rotated at very high speed.
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Character is printed by striking hammer against
embossed character on surface.
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Speed is 300 to 2000 lines per minute.
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They are very fast in speed.
BACK