The document summarizes different types of computer output devices and technologies. It discusses cathode ray tube (CRT) and liquid crystal display (LCD) computer screens, including resolution standards. It also covers impact and non-impact printers such as dot matrix, laser, and inkjet printers. Additionally, it mentions voice output using speech synthesis, as well as music output and sounds through speakers, sound cards, and MIDI interfaces.

1. Chapter 5 B.M.H Input and Output

2. Learning Objectives Computer Screen CRT (Cathode Ray Tube) LCD (Liquid Crystal Display) Printer Impact printer Nonimpact printer Voice output Music output and other sounds

3. Computer system Input Processing Output Secondary Storage

4. Output: information for the user Computer output screen printer output voice sound various form of graphics output

5. Computer Screen Monitor components the housing for its electrical components a stand that can be tilted or swiveled a screen Screen output Known in the computer industry as soft copy Intangible and temporary  Hard copy Output by printer on paper Tangible, permanent

6. Computer Screen Types of screen technology C athode R ay T ube (CRT) The most common kind L iquid C rystal D isplay (LCD) Eletric beam Eletric gun Displayer Red,Green,Blue

7. Cathode Ray Tube (CRT) Types according to color Most CRTs are color Some are monochrome Only one color, usually green or amber (yellowish-brown color) Less expensive than those with color

8. CRT Technology Called raster scanning A process of sweeping electron beams across the back of the screen The backing of the screen display Has a phosphorous coating that glows whenever it is hit by a beam of electron The phosphorous does not glow for very long The image must be refreshed often

9. CRT  Phosphorous : (Symbol P) a chemical element found in several different forms, including as a poisonous, pale yellow substance that shines in the dark and starts to burn as soon as it is placed in air  Electron : a very small piece of MATTER (= a substance) with a negative electric CHARGE, found in all atoms

10. CRT Scan rate The number of times the electron beam refreshed the screen 80 to 100 times per second Adequate to retain a clear screen image

11. CRT Has hundreds of horizontal lines scanned for left to right and from top to bottom Interlaced fashion The odd-numbered lines on one pass of the electron beam And then the even-numbered lines on the next pass - a lower refresh rate without producing flicker - Inexpensive monitors - with text and fixed graphics displays Noninterlaced (NI) All lines are scanned on each pass - With animated graphics

12. Computer Screen Is divided into dots Called addressable they can be addressed individually by the graphics SW Each dot Referred to as a pic ture el ement, or pixel Dot pitch the amount of space between the dots

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14. Computer Screen The Resolution of the screen the power of a computer screen to give a clear image Factors related the number of pixels on the screen The more pixels, the higher the resolution Dot pitch The smaller the dot pitch, the better the quality of the screen image

15. Computer Screen Chips affixed to the motherboard Convert the electrical output signals of the control unit into the signals that control the monitor To upgrade the graphics capability Most used graphics card , or graphics adapter board, plugged into a expansion slot

16. Graphic Standards The intention of standards To agree on resolutions, colors and so forth to make it easier for the manufacturers of PCs, monitors, graphics boards to ensure that their products work together

17. Graphic Standards CGA (Color Graphics Adapter) 320(horizontal)x200(vetrical) pixels EGA (Enhanced Graphics Adapter) 640x350 pixels VGA (Video Graphics Array) 640x480 pixels

18. Graphic Standards The standards in most common use today SVGA (Super VGA) Provide different resolution 800(h)x600(v), 1024x768, 1280x1024, 1600x1200 pixels Support a palette of 16million colors But simultaneous colors which can be displayed is limited by the amount of video memory installed in a system XGA (eXtended Graphics Array) High-resolution graphics standard The same resolution but more simultaneous color Allows to be noninterlaced

19. Computer Screen Screen sizes Measured diagonally 15-or 17-inch screen : a typical office worker handling word processing and spreadsheet  1 inch = 2.54 cm 19-inch screen : a user involved with high-powered graphics Bigger is usually better, more expensive

21. Liquid Crystal Display (LCD) Flat-Panel Screens Commonly used on laptop computers Basic technologies Active-matrix Based on TFT (thin-film transistor technology) Brighter image Can be viewed from wider angles Passive-matrix Fewer transistor cheaper, less power Easy on the eyes; not flicker, brightly shine on Higher price than CRT

24. Printer A device that produces information on paper output Two orientation settings  Orientation : the direction in which an object faces Portrait mode Default setting Printed in a vertical alignment Suited for graphics images Landscape mode Sideway or horizontally Useful for spreadsheets that have a lot of data across the sheet

25. Printer Two ways of printing an image on paper Impact printer Uses some sort of physical contact with paper to produce a image Types Line printers : mainframe Dot-matrix printers : PC Nonimpact printer Places an image on a page without physically touching the page Types Laser printers Ink-jet printers

26. Printer Measure Quality dpi : Dots Per Inch 600 ~ 1200 dpi Speed ppm : Pages Per Minute 8 ~ 10ppm

27. Impact printer 24x24, 10x10 Dot matrix

28. Laser printers Use a light beam to help transfer images to paper High-quality results Today, print 600 or 1200 dpi Print a page at a time at impressive speeds Printing speeds of personal laser printers : around 8 to 10 ppm Network printer : 35 and 50 ppm Banks and insurance use 1000ppm

30. Data from computer->positive charged drum is neutralized ->Toner sticked during passing by Toner -> Toner transferred to the paper ->heat and pressure fuse the Toner to the paper -> clean drum

31. Ink-jet printers Spray in from multiple jet nozzles Print in both black and white and several different colors of ink Low quality , not speedy Need a fairly high quality of paper Cost : little more than a hundred dollars

33. Ink-jet printers

34. Voice Output Speech synthesis The process of enabling machines to talk to people Accomplished through voice synthesizers (voice-output devices or audio-response units) Two approaches to getting a computer to talk Synthesis by analysis The computer analyzes stored tapes of spoken words Synthesis by rules The computer applies linguistic rules to create artificial speech Ex) airline, bus terminals, banks,

35. Music Output and Other Sounds Speaker Sound output devices Multimedia A certain kind of software for good-quality software Including multiple sight and sound effects An integrated collection of computer-based media including text, graphics, sound, animation, photo images and video Sound card Contain sophisticated audio chips Enhance the listening experience by varying the frequencies and timing of the sound waves

36. Sound card

37. Music Output and Other Sounds MIDI ( M usical I nstrument D igital I nterface) A set of rules designed for connecting devices that produce and process digital music signals Devices that conform to the MIDI standard Can communicate with each other and with a computer containing a MIDI interface Two musical devices Can communicate via MIDI The information exchanged between two MIDI devices Is musical in nature Supported by many makers of PC sound cards