Output Devices

Any items of hardware that the computer uses to present data to the user –Can output text, images, video, sound or other types of data –Movements can also be output using robotic arms

Screens One output device found in almost all computer systems –CRT - (cathode ray tube) displays are the big, deep monitors that used to be used on almost all desktop computers. –LCD (Liquid Crystal Displays) - have now replaced most CRTS Generally cheaper, thinner, lighter and produce higher quality images than CRT displays Small size is useful when displays need to be in confined spaces or portable devices

LCD Screens Native resolution - LCD screens have a native resolution, which refers to the fixed number of dots that make up the screen –Although an LCD can display an image in different resolutions, the image will be scaled to match the LCD’s native resolution Thus, the best image quality is obtained using an LCD at its native resolution

Display Output Devices Projector –shows data at a much greater size than CRT or LCD will allow, usually to a large audience Interactive white boards –Combination of projector and touch screen

Speakers Speakers have essential functions other than entertainment –In busy environments where a person must absorb a lot of info at once, like an aircraft cockpit, some feedback can be given as audio output Like beeps or a human voice –Useful in emergency situationswhere sound is more likely to be noticed than flashing lights or displays

Printers –Printers Produce hard copies of documents and files –Printers vary in how they produce an image »DPI (dots per inch) - quality of printer can be measured by the dots per inch that the printer is able to produce »This has a direct effect on the quality of the printout and the cost of the printer »The speed of a printer, expressed in pages per minute, may also be a factor –Dot matrix printers - obsolete now, noisy, slow, hit paper through an ink ribbon, like a typewriter –Inkjet printers »Squirt ink onto a page through a series of nozzles –Laser printers »Produce higher quality printouts than inkjet printers, but are also more expensive, especially color versions »Print at up to 40 ppm