Output Devices and Technologies: Monitors, Printers, Speakers, and More - Prof. Wooyoung K, Study notes of Computer Science

Download Output Devices and Technologies: Monitors, Printers, Speakers, and More - Prof. Wooyoung K and more Study notes Computer Science in PDF only on Docsity! Page 1 of 9 Chapter 6: Output What is Output? • Data that has been processed into a useful form, called information o Text o Graphics o Audio o Video What Are Output Devices? What is an output device? • Any hardware component that can convey information to a user o Printer o Monitor o Speakers Display Devices What is a display device? • Television-like • Information on a display device sometimes is called soft copy What is a CRT monitor? • Large sealed, glass screen • Screen coated with tiny dots of phosphor material • Pixel, or picture element, is single point in electronic image • Three dots (red, blue, and green) combine to make up each pixel What are typical sizes for CRT monitors? • 15, 17, 19, 21, and 22 inch screen size • Viewable size is diagonal measurement of actual viewing area provided by the monitor o Screen size o Viewable size What is a liquid crystal display (LCD) monitor? • Type of flat-panel display • Uses liquid crystals between two sheets of material to present information on screen • Electric current passes through crystals, which creates images on the screen Where are some features of LCD screens? • Lightweight and compact • Consumes less than one-third of the power than does a CRT monitor Page 2 of 9 • Ideal for notebook and handheld computers What is a Web-enabled device? Allows access to the Web or e-mail Cellular telephones Pagers Many use monochrome LCD displays to save battery power What is an electronic book (e-book) ? Small, book-sized computer that uses an LCD screen Allows users to read, save, highlight, bookmark, and add notes to online text Download new book content from Web What are the two technologies used for LCD monitors? Active-matrix display Can display high-quality color viewable from all angles Passive-matrix display Color often not as bright Images best viewed when working directly in front of display What is a gas plasma monitor? Flat-panel display uses layer of gas plasma between two sheets of material What is display resolution? Describes the sharpness and clarity of image The higher the resolution, the sharper the image and the more that can display on the monitor 800 x 600 most common 800 horizontal pixels 600 vertical pixels Total of 480,000 pixels on screen 1280 x 1024 maximum resolution of most monitors 2048 x 1536 maximum for high-end monitors What is dot pitch? Measure of the distance between pixels Sometimes called pixel pitch Smaller the distance between the pixels, the sharper the image Use a monitor with a dot pitch of .29 millimeters or lower to minimize eye fatigue What is refresh rate? Speed at which monitor redraws images on the screen Page 5 of 9 When ribbon presses against paper, it creates dots that form characters and graphics A higher number of pins (9 to 24) means printer prints more dots per character, which results in higher print quality What is a line printer? High-speed impact printer that prints entire line at a time Speed measured by number of lines per minute (lpm) it can print Band printer prints fully-formed characters using a hammer mechanism Shuttle-matrix printer is high-speed printer that works more like a dot-matrix printer What is a non-impact printer? Forms characters and graphics on piece of paper without actually striking paper Ink-jet Printer Laser Printer Thermal Printer What is an ink-jet printer? Nonimpact printer forms characters and graphics by spraying tiny drops of liquid ink onto piece of paper Most popular type of color printer for home use What is the resolution of a printer? Sharpness and clarity of characters Measured by number of dots per inch (dpi) printer can output 300 dpi 600 dpi 1,200 dpi How does an ink-jet printer work? 1: Small resistor heats ink, causing ink to boil and form vapor bubble 2: Vapor bubble forces ink through nozzle 3: Ink drops onto paper 4: As vapor bubble collapses, fresh ink is drawn into firing chamber What is a laser printer? High-speed, high-quality nonimpact printer Prints text and graphics in very high-quality resolution, ranging from 600 to 1,200 dpi Typically costs more than ink-jet printer, but is much faster How does a laser printer work? 1: Drum rotates as paper is fed through 2: Mirror deflects laser beam across surface of drum Page 6 of 9 3: Laser beam creates charge that causes toner to stick to drum 4: As drum rotates, toner transfers from drum to paper 5: Rollers use heat and pressure to fuse toner to paper What is a thermal printer? Generates images by pushing electrically heated pins against heat-sensitive paper Ideal for small devices, such as adding machines What is a photo printer? Color printer that produces photo lab quality pictures and prints everyday documents What is a label printer? • Small printer that prints on adhesive type material that can be placed on a variety of items • Most also print bar codes and e-stamps What is a portable printer? • Small, lightweight ink-jet or thermal printer that allows mobile user to print from notebook or handheld computer while traveling What is a plotter? • Sophisticated printer used to produce high-quality drawings • Large-format printer similar to plotter and is used to print quality color prints Speakers and Headsets What is an audio output device? • Computer component that produces music, speech, and other sounds (.wav files) • Speakers and headsets are common devices What is voice output? • Computer talks to you through speakers on computer o RealPlayer What is Internet telephony? • Allows you to have a conversation over the Web, just as if you were talking on the telephone Other Output Devices What is a data projector? • Device that takes image from a computer screen and projects it onto a larger screen What is a facsimile (fax) machine? • Device that transmits and receives documents over telephone lines What is a fax modem? • Modem that allows you to send and receive electronic documents as faxes o External fax modem Page 7 of 9 o Internal fax modem card in system unit • Must have OCR software to convert to characters What is a multifunction device (MFD) ? • Provides the functionality of a printer, scanner, copy machine, and fax machine o All in one Terminals What is a terminal? • Device that performs both input and output o Dumb terminals o Intelligent terminals o Special-purpose terminals What is a dumb terminal? • Has a keyboard and monitor, but no processor or memory • Connects to host computer that performs processing and then sends output back What is an intelligent terminal? • Has monitor, keyboard, memory and processor • Similar to a PC in that it can perform tasks independent of host computer • Programmable Special Purpose Terminals What is a point-of-sale (POS) terminal? • Records purchases at point where purchase is made • Output from POS terminals serves as input to host computer o POS terminal in a grocery store o Scanner and keyboard are input What is an automated teller machine (ATM)? • Self-service banking machine that connects to host computer through telephone network Output Devices for Physically Challenged Users What is the Magnifier command? • Windows Magnifier command enlarges text and other items in window on screen What other output options are available for visually impaired users? • Change Window’s settings such as increasing size or changing color of text to make words easier to read • Blind users can work with voice output