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AS Computing. 5.1.5. Hardware. Common peripheral devices. A peripheral is “ a piece of equipment (or hardware) which can be connected to the control processing unit. They are used to provide input, output and backing storage for the computer system.”. Input devices. Keyboard Mouse
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AS Computing 5.1.5. Hardware
Common peripheral devices A peripheral is “ a piece of equipment (or hardware) which can be connected to the control processing unit. They are used to provide input, output and backing storage for the computer system.”
Input devices • Keyboard • Mouse • Bar code reader • Joysticks and consoles • Touch screen and pen-based input devices
Storage devices • Primary storage • RAM • ROM • Cache • Secondary Storage • Magnetic disk: hard disk, floppy disk • Magnetic tape: film tapes • Optical disk: CD, DVD
Output devices • Printers • Dot matrix printers • Inkjet printers • Laser printers • Plotters • Visual Display Units • Speakers • Headphones
Dot Matrix Printers • Dot matrix printer is relatively slow and noisy. • The quality of the hard copy is relatively poor compare to Inkjet and laser printers. • It is an old technology. Their uses are limited now. • The hard copy is made by pins striking paper.
An example of use of Dot Matrix Printers Dot matrix printer is used by credit card companies to produce receipts when a customer makes a purchase. Alter a customer ‘s credit card us swiped and authorised, two identical copies of a receipt are printed using small dot matrix printers.
Inkjet printers • This type of printer ‘sprays’ ink onto paper. • It can produce high quality black and white as well as colour copies. • It is suitable for small business or home use. • It is suitable for small amounts of printing, owing to its slow speed and the high cost of ink.
Laser printers • Laser printer can produce very high quality black and white. • It is very expensive in colour. • It is cost more to buy and run than Inkjets.
Plotters • Plotters are used to produce very large drawings • Plotters can produce very high quality, very accurate, colour drawings. • They are relatively expensive compared to printers. • Flatbed X-Y plotter: A plotter using a bed or tray to hold paper in a fixed position. A single arm moves a pen both horizontally and vertically on the paper to produce inked output. This is the more economical version of a plotter.
Visual Display Units • Monitors are ideal for displaying data and information to users. • CRT is stand for Cathode Ray Tube. • This technology is used in most televisions and computer display screens. • TFT is short for thin film transistor. • It is a type of flat panel liquid crystal display screen (LCD), in which each pixel is controlled by from one to four transistors.
CRT display • Size range from about 14 in to 26 in for high-resolution colour monitor. • Resolutions range from 800 by 600 to well in excess of 1280 by 1024. • The large monitor are needed to display these very high resolutions.
Liquid crystal displays (LCD) • LCD represent the thin screens, which appear on most portables. • Much larger LCD displays are available, up to 48 in and beyond. • Recent innovations are light emitting plastics (LEP) displays, which are paper thin. • Theoretically IEP can be of any size.
Speakers and headphones • Speaker is an equipment that accepts audio signals from an amplifier and converts them into sound waves for listening at some distance. • Headphones are a device that you can use to listen to music.