User:Output devices eme2040

OUTPUT DEVICES An output device is any machine that is able to communicate information from a computer. Many familiar output devices are display devices, printers, data projectors, facsimile machines, multifunction devices, speakers, headphones, and earphones.

DISPLAY DEVICES Display devices are output devices that are able to show text, graphics, and video information. An example of this is a monitor. Sometimes information on a display device is also called a soft copy. Information is called this because sometimes it will appear electronically and will only be displayed for a short period of time. Monitor screens come in many different sizes. Like televisions, they are measured in diagonal inches from corner to corner. Monitors that are sixteen inches or more diagonally are called full page monitors. Monitors can either be portrait (height greater than width) or landscape (width greater than height). One can adjust the angle of the screen to reduce neck strain and glare by using its tilt and swivel base.

CRT MONITORS CRT stands for cathode-ray tube. It is the technology used in most televisions and computer display screens. CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, which then illuminates the active portions of the screen. By drawing many such lines from the top to the bottom of the screen, it creates an entire screen full of images.

FLAT-PANEL DISPLAYS A flat-panel display is a very thin display screen usually used in portable computers. They usually use LCD (liquid crystal display) technologies. The LCD screens are backlit so they are easier to use and read in bright lit areas. Examples of flat-panel displays include LCD monitors, LCD screens, and plasma monitors.

LCD MONITORS AND SCREENS An LCD monitor is also called a flat-panel monitor. These lightweight desktop monitors take up little desk space and create sharp, flicker-free images using a liquid crystal display. Liquid crystal display is a technology LCD monitors use by utilizing two sheets of polarized material with a liquid crystal solution between them. The crystals are then caused to align so that light is not able to pass through them. This is done using an electric current which passes through the liquid.

PLASMA MONITORS A plasma display works by sandwiching neon gas between two glass plates. When an electric current is applied ultraviolet light is released from the gas which causes the pixels on the screen to glow and form an image. Think of it as a collection of small neon bulbs. Plasma monitors are very expensive however they offer many enticing features such as larger screens and richer colors than LCD monitors. RESOLUTION Resolution is the number of horizontal and vertical pixels in a display device. A monitor that has a 1280 X 1024 resolution has 1280 pixels per horizontal row and 1024 pixels per vertical row. It takes a total of 1,310,720 pixels to make a full screen image.

TELEVISIONS The output device for game consoles like the Xbox 360, Nintendo Wii, and the Playstation 3 is often a T.V. One end of the cable plugs into the T.V and the other into the console.

PRINTERS A printer is an output device that provides text and graphical information on to paper. It can be printed into either landscape or portrait orientations. Landscape orientation is where the paper is wider than tall. Portrait orientation is where the paper is taller than wide.

NON-IMPACT PRINTERS A non-impact paper does not operate by striking a head against a ribbon like more traditional printers do. The two most common types are inkjet printers and laser printers. Inkjet printers form marks by spraying tiny drops of liquid ink onto a piece of paper. They can produce high-quality text and graphics in both black and white or color. A laser printer is a high speed, high quality non impact printer. Laser printers are more expensive than inkjets and they print faster.

Data Projectors An output device that projects an image the displays on a computer screen onto a large screen, so that an audience, such as a classroom or school assembly, can see the image clearly. They range in size from large devices attached to a ceiling or wall to smaller portable devices. Two types of smaller and lower cost devices are the LCD and DLP projectors. LCD stands for liquid crystal display and DLP stands for digital light processing and it uses tiny mirrors.

Facsimile Machine A fax machine is a device that transmits and receives documents over telephone lines. Faxes can contain text, photos and graphic’s or can be handwritten. The fax machine scans the original copy and converts it into digitized data and sends this information to the fax machine on the other end were it converts it back into a copy of the original that is a stand alone. There is also what is called a fax modem which allows you to fax using your computer.

Multifunction Devices A multifunction device is a single device that provides the functionality of a fax, printer, scanner and copier. The features of these machines very widely, for example some are color ink-jet technology while others use black and white laser printer. Some of the places they are used are small businesses, schools, home offices and numerous other they use them because it saves space.

Speakers, Headphones, and Earphones Speakers, headphones and earphones are all audio output devices in order to use these you have to have voice output. Voice output occurs when you hear a person’s voice or when the computer talks to you through the speakers. One the newest and most amazing things we can to is make a word document with voice output. An audio output device is a component of a computer that produces music, speech, or other sounds, such as beeps. The three most common are speakers, headphones and earphones. Speakers can be separate devices placed on either side of the monitor or they can be built into the monitor. There are tone and volume controls for the speakers. Speakers are not always practical in a classroom or computer lab so the alternative is headphone or earphones. These can be plugged into the computer so that nobody distracts each other with the sounds of there computer. The difference between headphones and ear phones is the headphones cover or are placed outside of the ear while earphones while ear phones go it the ear canal.

Citations

Booth, Paul A. An Introduction to Human-Computer Interaction. Psychology Press, 1989.

Hodges, M. Susan. Computers: Systems,Terms, and Acronyms. Semco Enterprises, 1999.