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Chapter 6 Output. Ch 4 Processor. Control Unit. Arithmetic Logic Unit (ALU). Instructions Data Information. Instructions Data Information. Ch 1 – Introduction Ch 2 – Internet & WWW Ch 3 – Application Software Ch 8 – System Software. Control Unit. Arithmetic Logic Unit ( ALU ).
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Ch 4 Processor Control Unit Arithmetic Logic Unit (ALU) InstructionsDataInformation InstructionsDataInformation Ch 1 – Introduction Ch 2 – Internet & WWW Ch 3 – Application Software Ch 8 – System Software Control Unit Arithmetic Logic Unit (ALU) OutputDevices Ch 6 InputDevices Ch 5 Information Data StorageDevices Ch 7
Output what? Information - processed, organized, meaningful, useful data text graphics video audio
speakers display printer
What is adisplay device? • Output device that visually conveys text, graphics, and video information • Information on display device is called soft copy • Monitorhouses display device as a separate peripheral
CRT (Cathode Ray Tube) Monitors • What is aCRT monitor? • Containscathode-ray tube (CRT) • Screen coated with tiny dots of phosphor material • Each dot consists of a red, green, and blue phosphor • Common sizes are 15, 17, 19, 21, and 22 inches • Viewable size is diagonal measurement of actual viewing area
What is an LCD monitor? • Uses liquid crystal display • Mobile devices that contain LCD displays include • Notebook computer, Tablet PC, desktop computer, portable media player, smart phone, and PDA
Using multiple LCD monitors • Some users position two or more monitors side-by-side or stacked • Allows users to run multiple applications simultaneously
Displays image by applying voltage to layer of gas • Larger screen size and richer colors than LCD, but plasma monitors are more expensive • What is aplasma monitor?
The graphics processing unit (GPU) controls the display of graphics
Interactive screen • More and more electronic screens are used to interact with the computer rather than just reflect information delivered by the computer. Interactive screen
The quality of a display depends on: Color depth
What isresolution? • Number of horizontal and vertical pixels in a display device • Higher resolution makes image sharper, displays more text on screen
600 vertical pixels 800 horizontal pixels 800 x 600most common 1280 x 1024maximum resolution of most monitors 2048 x 1536maximum for high-end monitors Total 480,000 pixels
Measure of the distance between pixels Sometimes called pixel pitch Smaller the distance between the pixels, the sharper the image What is dot pitch? Use a monitor with a dot pitch of .29 millimeters or lower to minimize eye fatigue
Number of bits a video card uses to store information (color) of each pixel Also called color depth Determines number of different colors The greater the number of bits (color depth) , the better are colors of the image What is bit depth? 8-bit video cardUses 8 bits to store information about each pixel Can display 256 different colors 28 =2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256 colors 24-bit video card Uses 24 bits to store information about each pixel Can display 16.7 million colors 224 = 16.7 million colors
Price of a display is the biggest part of the computer price • Screenresolution: more pixels – sharper picture • What is important in a monitor? • Dot pitch: distance between neighboring pixels • Color depth: more bytes to carry the color of a pixel • Refresh rate is speed at which monitor redraws images on screen • Energy consumption
Television From 3 channels to 300 From analog to digital From TV to HDTV Next is streaming
What isdigital television (DTV) Many programs can bebroadcast on a singledigital channel DTV uses digital signals to producecrisper, higher-quality outputon LCD and plasma televisions
What ishigh-definition television HDTV)? High resolution HDTV (high-definition television)is the most advanced formof digital TV Great for game playing, watching movies, and browsing the Internet
Using a computer to deliver television • Just a few years ago it seemed far-fetched: there was not much video online that was legal and non-pornographic; broadband wasn’t available • That has changed. Here are some video-streaming websites: iPlayer, Hulu, YouTube that stream billions of videos per month • Ordinary people want a cable that will allow them to connect their computers to their television sets
Three-dimensional TV is coming Three-dimensional TV works by projecting two images filmed from slightly different angles onto the screen. Battery-powered glasses ($150 for two sets) alternately darken each lens, so each eye sees only one of two images “Monsters v Aliens”, “Avatar”, “My Bloody Valentine 3D”, televised sport will gain the most. Sport is the “killer application” of today's TV
What is theENERGY STAR program? • Encourages manufacturers to create energy-efficient devices that require little power when not in use • Monitors and devices meeting guidelines display ENERGY STAR label
Computer component that produces music, speech, or other sounds • What is anaudio output device? • Speakers and headsets are common devices
Headphones are speakers that cover your head or are placed outside of the ear • Ear buds (also called earphones) rest inside the ear canal
Some speakers are specifically designed to play audio from a portable media player • Wireless speakers
Printers portrait landscape • What is aprinter? • Output device that produces text and graphics on a physical medium (paper, film, fabric) • The result is the hard copy, orprintout • Two orientations: • portrait • landscape
Nonimpact printer • forms characters and graphics on a piece of paper without actually striking the paper
Ink-jet printer • Ink-jet printersprays tiny drops of liquid ink onto paper • Prints in black-and-white or color on a variety of paper types
print head print cartridge firing chamber ink dot bubble resistor ink nozzle • How does an ink-jet printer work? Step 1. A small resistor heats the ink, causing the ink to boil and form a vapor bubble. Step 2. The vapor bubble forces the ink through the nozzle. Step 3.Ink drops onto the paper. Step 4. As the vapor bubble collapses, fresh ink is drawn into the firing chamber.
A thermal printergenerates images by pushing electrically heated pins against the heat-sensitive paper
A mobile printeris a small, lightweight, battery-powered printer that allows a mobile user to print from a mobile device
A label printeris a small printer that prints on adhesive-type material • A postage printer prints postage stamps
Sophisticated printer used to produce high-quality drawings • Large-format printercreates photo-realistic-qualitycolor prints • What is aplotter?
A multifunction peripheral(MFP) is a single device that prints, scans, copies, and sends faxes • Sometimes called an all-in-one device
Impact printer • dot-matrix: • produces printed images when tiny wire pins strike ribbon • band:prints fully formed characters using a hammer mechanism
High-speed impact printer that prints entire line at a time • Some line printers are band printers • Others are shuttle-matrix printers • What is aline printer?
Characteristics of a Printer Price Speed Colorvs.black- white Graphics and photo printing Cost per page Portable/ Stationary Resolution Paper types and sizes Wireless capability System compatibility
Sharpness and clarity • What is theresolutionof a printer? • Measured by number ofdots per inch (dpi)printercan output
What is a terminal? Device that performs both input and output Terminals special-purpose terminals dumb terminals intelligent terminals