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• Cathode ray tubes (CRTs): are similar in size and technology to older televisions but have been replaced by flat panel monitors .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