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Output devices Output :is processed data or information.
Output devices: hardware devices that translate information that has been
processed by the system unit to a form that humans can understand.
Monitors
Most frequently used output device . Also known as display screens.
Presents visual images of text or graphics .
Output is often referred to as soft copy.
They can vary in size , shapes and cost but has the same basic features.
Features
• Clarity : The most important feature refers to the quality and sharpness of the displayed images.
• Resolution :Images are formed in a monitor according to a series of dots or pixels (picture elements ).
For example a monitor might have a resolution of 1600 pixels column by 1200 row . The higher the resolution the clearer the image produced.
• Dot (pixel)pitch: The distance between each pixel. The lower the dot pitch the clearer the image.
Features 2
• Contrast ratios :Indicates the monitors ability to display colors .It compares the light Intensity from the brightest white to the darkest black. The higher the better .
• Size or active display area :Measured by the diagonal length of a monitors viewing area. Common sizes are 15.17.19.21.24 inches.
• Aspect ratio :The width of the a monitor divided by its height.
Most common are 16:9 and 16:10
Flat Panel Monitors
The most widely used type of monitor today
LCD: (liquid crystal display )
E-books readers
• Electronic books.
• Mobile devices to store and display eBooks and other electronic media .
• Use e link technology : produces images that reflect light like ordinary paper makes the display easy to read.
• Tablets can display e-books but are heavier , more expensive and more difficult to read in bright light .
Other monitors
• Digital or interactive whiteboards :specialized devices with a large display connected to a computer or a projector. Widely used in class rooms and boardrooms.
• High definition television (HDTV):Delivers a much clearer and more detailed wide screen picture than a regular television .Most useful to graphic artists , designers and publishers.
• Cathode ray tubes (CRTs): are similar in size and technology to older televisions but have been replaced by flat panel monitors .
Discarded CRTs are a serious threat to our environment because each color contains a lot of lead.
Printers
• Translate information that has been processed by a system unit and present the information on paper.
• Printer output is called a hard copy .
Features
• Resolution :similar to monitor a measure of clarity .However , is measured in dpi (dots per inch). The higher the dpi the better the quality .
• Color :The ability to print with just black or colored.
Grayscale is the most common black ink in which images are displayed using many shades of gray .
• Speed : measured in the numbers of pages printed per minute . (15-19 in average)
• Memory :within a printer is used to store printing instructions and documents waiting to be printed.
• Duplex printing :Allows automating printing in both sides of the paper.
Types of Printers
• Inkjet printers :spray ink at high speed onto the surface of the paper .
Most widely used type of printer .Its reliable, quiet and inexpensive .
It replaces the link cartridges.
• Laser printers :use technology similar to photocopying machine involving laser beam to produce high quality images. Two categories :
Personal : less expensive used by a single user .
Shared: supports color, more expensive and supports groups of uses.
Other printers