Last week, group Y.E.S have presented a topic on input and output devices.
INPUT:
Input ports are connections at the back of a computer.
Input devices are connected to these ports.
Examples: keyboard which is used to type data into a computer.
There are many type of keyboards that are created to give comfortable for the user
such as:
There are many type of keyboards that are created to give comfortable for the user
such as:
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| Strange keyboard |
 |
| Joystick keyboard |
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| Ergo keyboard |
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| Flexible keyboard |
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| Virtual keyboard |
Scanner :
- An inexpensive way to get entire documents, pictures, and anything.
- Scanners use optical recognition systems that have a light beam to scan input data to convert it into electrical signals, which are sent to the computer for processing.
- Optical recognition is by far the most common type of source input, appearing in a variety of ways:
- optical marks
- optical characters
- bar codes
- handwritten characters
- images
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| Barcode |
Scanners use Optical Character Recognition software:to translate text on scanned documents into text that is suitable for word processors and other computer applications.
OUTPUT:
We have chosen to write about the difference of type of the televisions that are related to this topic.
PLASMA TELEVISIONS
-used technology based loosely on the fluorescent light bulb
-the display itself consists of cells
-each cell two glass panels are separated by a narrow gap: neon-xenon gas is injected & sealed in plasma during
manufacturing process
-charged gas strikes red, green and blue phosphors, thus creating television image
-each group of blue, red and green phosphors are called pixel (picture element)
-Plasma also suffer some of the drawbacks of the traditional televisions such as heat generation and screen-burn of static images
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| PLASMA TV |
LCD TELEVISIONS
-flat panel television which utilizes a Liquid Crystal Display technology
-has two layers of glass which are polarized and stuck together
liquid crystals are held in one of the layers: it pass or block the light to produce images on the screen
-the crystals does its own light but it is using the fluorescent lamps": make the images become visible to the viewer
-LCD televisions produces high image quality, appealing to buyers
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| LCD TV |
LED TELEVISIONS
-same to LED televisions but different in the source of light which is at the back of the screen
-LCD televisions use fluorescent lamps whereas LED televisions use LED (Light Emitting Diodes)
-two types of LED backlighting:
-Edge Lighting :series of diodes are arranged along the outside edges of the screen, light distribute to the
screen
-Full-Array Lighting : several rows of diodes behind the entire surface of the screen-provide more
control brightness and dimming
-LCD television are the newest version,use new backlight system and more expensive than other televisions
 |
| LED TV |
REFERENCES :
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