Cs chapter 3


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Cs chapter 3

  1. 1. BIT Semester 1 Computer Systems Chapter 3 Input and Output Devices
  2. 2. Input Devices <ul><li>The devices that are use to input ‘Data’ to the computer. </li></ul><ul><li>Most Common input devices of the computer are, </li></ul><ul><ul><li>Keyboard </li></ul></ul><ul><ul><li>Mouse </li></ul></ul>
  3. 3. Keyboard <ul><li>The primary input device of the computer. </li></ul><ul><li>Using the keyboard you can do the simplest Input functions of entering data and commands to your computer system. </li></ul><ul><li>Has a similar layout to the typewriter. </li></ul><ul><li>but has some additional keys that provide additional functionality than a typewriter. </li></ul>
  4. 4. Keyboard Cont…. <ul><li>Keyboards come in different shapes and sizes but may different the number of additional keys. </li></ul><ul><li>The keyboards may be connected to the computer system through a wire or as wireless. </li></ul><ul><li>The wired connection may be through the DIN( Deutsches Institute für Normung) -5connector, PS/2connector or USB. The wireless may use radio-frequency or infrared. </li></ul>
  5. 5. Keyboard Types
  6. 6. Standard Keyboards <ul><li>The standard keyboard has one hundred keys. This set of keys can be divided in to six categories. </li></ul><ul><ul><li>Alphanumeric keys </li></ul></ul><ul><ul><li>Modifier keys </li></ul></ul><ul><ul><li>Numeric keypad </li></ul></ul><ul><ul><li>Function keys </li></ul></ul><ul><ul><li>Cursor-Movement keys </li></ul></ul><ul><ul><li>Special-purpose keys </li></ul></ul>
  7. 7. Alphanumeric keys <ul><li>These include the alphabetical and numeric keys grouped together on the left side of the keyboard. </li></ul><ul><li>The main function of these keys is to simply enter what ever symbol that is displayed on the particular key. </li></ul>
  8. 8. Modifier keys <ul><li>These keys are located on the bottom left and right corners of the grouping of the alphanumeric keys. </li></ul><ul><li>These keys include “Shift, ”Ctrl”, Alt” </li></ul><ul><li>Should use with another supporting key to modify. E.g.- Ctrl+C, Ctrl+V, Alt+F4 </li></ul>
  9. 9. Numeric keypad <ul><li>These are the set of keys that are located at the right most end of your keyboard. </li></ul><ul><li>These help to enter numeric data faster that using the alphanumeric keys. </li></ul>
  10. 10. Function keys <ul><li>These are the keys located on the top most row of the keyboard and labeled F1toF12. </li></ul><ul><li>These keys are allocated certain functions by different applications. E.g-F1-Help </li></ul>
  11. 11. Cursor-Movement keys <ul><li>These cursor keys include the quad-directional arrows keys and the&quot; Home, End, Page-up, Pagedown”keys are the movement keys. </li></ul>
  12. 12. Special-purpose keys <ul><li>Special keys usually located between the alphanumeric and number-pad keys which allow you to carry out special functions. </li></ul><ul><li>These keys are the “Insert (also known as the over write), Delete, Print screen, Scroll Lock, Pause and Esc” </li></ul>
  13. 13. Special keyboards <ul><li>According to the users requirements the keyboard structure radically changed. </li></ul><ul><ul><li>101-key enhanced keyboard </li></ul></ul>
  14. 14. 104-key Windows keyboard <ul><li>Two Windows keys and One Application Key attached to the keyboard. </li></ul>
  15. 15. Mac keyboard <ul><li>Similar to 101-keyborad. </li></ul><ul><li>But specially use within Apple Mac O/S. </li></ul>
  16. 16. Multimedia and Web-enabled keyboards <ul><li>Enable you launch you multimedia players and control your media player. </li></ul><ul><li>Support Many media facilities. </li></ul>
  17. 17. Ergonomic keyboards <ul><li>The term “ergonomic” implies that’ something's designed to optimize human well-being, overall system performance and human comfort </li></ul>
  18. 18. Pointer Devices
  19. 19. Pointer Devices <ul><li>Any location on the computer screen can be addressed by using X-Y coordinates. </li></ul><ul><li>Pointer devices as the name implies are used to point to specific location on the computer screen. </li></ul><ul><li>According to the movement of the device screen pointer moves. </li></ul>
  20. 20. Mouse <ul><li>The second most common input device (after keyboard) is Mouse. </li></ul><ul><li>The X-Y Position indicator for a display system was invented by Mr. Douglas Englebartin 1964. </li></ul><ul><li>This device was later </li></ul><ul><li>called the mouse. </li></ul>
  21. 21. Mouse cont…… <ul><li>The mouse comprises of four parts. </li></ul><ul><ul><li>A ball/roller or optical sensors that indicate the mouse motion. </li></ul></ul><ul><ul><li>Buttons and/or wheel that are used to make selections and scroll. </li></ul></ul><ul><ul><li>A housing that holds the above components and lets you move the mouse around </li></ul></ul><ul><ul><li>An interface to connect to the computer system. </li></ul></ul>
  22. 22. Ball Mouse <ul><li>The Ball mouse uses a ball/roller. </li></ul><ul><li>When the mouse is moved the perpendicular wheels touching the ball moves and sensors at the end of these wheels indicate the direction of motion. </li></ul><ul><li>The disadvantage of the ball mouse is that it gathers dust and trash ,which cause unreliable motion. </li></ul>
  23. 23. Optical Mouse <ul><li>The optical mouse uses a light and an optical sensor. </li></ul><ul><li>Advantages- </li></ul><ul><ul><li>More reliable to perform smoother operations. </li></ul></ul><ul><ul><li>Light weight. </li></ul></ul><ul><ul><li>No dust problems. </li></ul></ul>
  24. 24. Mouse cont…. <ul><li>The mouse rolls on a flat surface. </li></ul><ul><li>The motion of the mouse is picked up by the sensors and passed through the interface to the computer system. </li></ul><ul><li>The system software decodes this motion data and appropriately moves the pointer on the computer screen. </li></ul><ul><li>The required task can be executed by clicking the mouse buttons. </li></ul>
  25. 25. Mouse interface….. <ul><li>The interface between the mouse and the computer system may be wired or wireless. </li></ul><ul><li>Wired connection by via PS/2 port or USB. </li></ul><ul><li>Wireless may use radio signal or IR. </li></ul>
  26. 26. Trackball <ul><li>The trackball works like an upside-down mouse. (Ball mouse) </li></ul><ul><li>The ball is on the top of the device where as the mouse ball is on the underside. </li></ul><ul><li>The mouse has to be moved around where as the trackball remains stationary. </li></ul><ul><li>All other functions are similar to mouse. </li></ul><ul><li>The best example is the use of a trackball in laptops where you do not have space for a mouse. </li></ul>
  27. 27. Touchpad <ul><li>The touchpad also known as Trackpad. </li></ul><ul><li>First invented at 1994. </li></ul><ul><li>This is a square area about 2 inches by 1.5 inches. </li></ul><ul><li>The finger is used to move around on the touchpad and this is similar to movement of a mouse-”Strike sensitive”. </li></ul><ul><li>Tapping the Touchpad is one way to give inputs or users can use provided buttons. </li></ul><ul><li>More common within ‘Notebook’ environments. </li></ul>
  28. 28. Pen-Stylus <ul><li>The stylus is used to write on a special pad or directly on the screen. </li></ul><ul><li>The pen is commonly used for data entry on PDAs, handheld computers, tablet PCs, smart phones and palmtops. </li></ul><ul><li>Clicking the mouse similar to tapping the screen or pad by using the “Pen”. </li></ul><ul><li>To enter characters using a ‘Virtual Keyboard’. </li></ul>
  29. 29. Touch Screen <ul><li>Is a display screen which has sensors or capacitive film to locate where the finger is touching the screen. </li></ul><ul><li>Act as a input as well as output device. </li></ul>
  30. 30. Touch Screen cont…. <ul><li>These are commonly used in locations where using a mouse or keyboard is not feasible and an intuitive interface is required. </li></ul><ul><li>The buttons or icons on the screen can be pressed by the finger or a Pen. </li></ul><ul><li>Very popular in ATMs , point of sales, mobile phones </li></ul>
  31. 31. Joystick and Game Pad
  32. 32. Joystick and Game Pad cont… <ul><li>Use to provide the gaming experience for the users with more entertainment. </li></ul><ul><li>By using these motion & sound becoming more and more realistic. </li></ul><ul><li>New devices connected via USB ports and users can very easily plug & play the device without using device drivers. </li></ul>
  33. 33. Optical Devices
  34. 34. Optical Devices <ul><li>Optical devices use light to capture data and input it in to the computer system. </li></ul>
  35. 35. Barcode readers <ul><li>Barcodes are a set of dark lines that are used to uniquely identify an item or product. </li></ul><ul><li>Barcodes are found in many products. (most of the International products) </li></ul><ul><li>This is a convenient way of entering data by simply swiping the printed barcode under the barcode reader. </li></ul><ul><li>These emits trips of LASER light and the reflected image is picked-up by the light sensors. </li></ul><ul><li>The captured image is processed and the barcode is identified and passed on to the computer system as an alpha numeric value. </li></ul><ul><li>This value can be processed by the program and a suitable response can be executed. </li></ul>
  36. 36. Scanners <ul><li>Scanners are used to capture printed image in to an electronic format. </li></ul><ul><li>Hard-copy input can be stored within a computer as soft-copy by using a Scanner. </li></ul><ul><li>This is done by shining light on to the image and capturing the wave length of light reflected a teach point of the image. </li></ul><ul><li>The wave length at each position is plotted to a two dimensional array that creates an electronic image file. </li></ul><ul><li>This image file can be stored within the computer. </li></ul>
  37. 37. The types of Scanners <ul><li>There are two types pf Scanners. </li></ul><ul><ul><ul><li>-Flatbed -Hand-held </li></ul></ul></ul>
  38. 38. Microphones <ul><li>The microphone is the device used to input sound into the computer system through the soundcard. </li></ul><ul><li>The microphone aids in recording speech, communicating though voice and providing voice commands. </li></ul><ul><li>Communication can be achieved through voice overIP telephony and voice chat. </li></ul><ul><li>If your computer system has voice recognition software it can recognize your voice command and execute appropriate actions. </li></ul>
  39. 39. Video Input <ul><li>Video input devices also referred to as video cameras come in many sizes, different recording qualities, different storage mediums and in analog and digital forms. </li></ul><ul><li>There are some types of Cameras, </li></ul><ul><ul><li>Web camera </li></ul></ul><ul><ul><li>Analog video camera </li></ul></ul><ul><ul><li>Digital video camera (DV and DVD) </li></ul></ul><ul><ul><li>camcorder </li></ul></ul>
  40. 40. Web Camera <ul><li>This type can be considered the most prehistoric type of video camera. </li></ul><ul><li>Where it captures the image and transfers it directly to the computer system. </li></ul><ul><li>Specially use within online video conferencing. (Cam-Chat) </li></ul><ul><li>The video quality was low comparing to the other cameras. </li></ul><ul><li>Not support to capture and transfer sound. </li></ul><ul><li>Now a days come up as a in built device with portable devices. </li></ul>
  41. 41. Analog video camera <ul><li>These can capture and store analog video on magnetic tapes. </li></ul><ul><li>These cameras also capture sound. </li></ul><ul><li>The main disadvantage is user need to have a special video capture card to convert the analog video in to digital format. </li></ul>
  42. 42. DV Camera <ul><li>The DV camera stores the audio and video on DV tapes in digital format. </li></ul><ul><li>Connect to the computer via “Fire-Wire” interface. </li></ul><ul><li>Fire-wire interface allow the control of the camera playback through a GUI on the computer system. </li></ul><ul><li>Disadvantage is data transfer time similar to recording time. </li></ul>
  43. 43. DVD Camera <ul><li>The DVD cameras directly write the video on to a mini-DVD/DVD. </li></ul><ul><li>These can be read using a DVD-ROM and copied to the computer using DVD-ripping software. </li></ul>
  44. 44. Camcorder <ul><li>The most convenient video cameras are those with digital memory cards that directly store the video and audio as a single file on the memory card. </li></ul><ul><li>When the user attach the device to the computer the content of the memory card will display as a disk drive. (similar like flash drive) </li></ul><ul><li>File can be simply copy. (Don’t need to convert) </li></ul><ul><li>The video quality is very high. </li></ul><ul><li>Easy to use than other devices. </li></ul>
  45. 45. Digital cameras <ul><li>The difference between digital cameras and video cameras is that digital cameras only captures still images and store them in a digital memory card. </li></ul><ul><li>Most often the image file is compressed and stored on the memory card to allow a large number of photographs to be taken. </li></ul><ul><li>The memory card is displayed like another disk drive on your computer system when you connect the digital camera to the computer system. </li></ul><ul><li>Users just need to copy items. (Don’t need conversion method) </li></ul>
  46. 46. Output devices <ul><li>The computer uses output devices to transfer information to the environment and the user. </li></ul>
  47. 47. Monitors <ul><li>The primary output device of the computer system. </li></ul><ul><li>Monitors provide us with a graphical representation of information on the screen. </li></ul><ul><li>Mainly there are two types, </li></ul><ul><ul><li>CRT </li></ul></ul><ul><ul><li>Flat-panel </li></ul></ul>
  48. 48. CRT <ul><li>CTR stands for Cathode Ray Tube. </li></ul>
  49. 49. CRT cont….. <ul><li>This is the technology commonly used in television sets. </li></ul><ul><li>The monitor tube is a glass vacuum tube with one end having an electron gun that projects three beams and the other a display surface coated with phosphors. </li></ul><ul><li>When the electron beam strike the coating it glows with the particular color. </li></ul><ul><li>The three electron beams are intended to glow the red , green and blue phosphors. </li></ul>
  50. 50. CRT elements <ul><li>1. Deflection coils </li></ul><ul><li>2. Electron beam </li></ul><ul><li>3. Focusing coil </li></ul><ul><li>4. Phosphor layer </li></ul><ul><li>5. Filament for heating the cathode </li></ul><ul><li>6. Graphite layer on the inner side of the tube </li></ul><ul><li>7. Rubber gasket where the anode voltage wire enters the tube </li></ul><ul><li>8. Cathode </li></ul><ul><li>9. Air-tight glass &quot;body&quot; of the tube </li></ul><ul><li>10.Screen </li></ul><ul><li>11.Coil yoke made of iron </li></ul><ul><li>12.Control electrode regulating the intensity of the electron beam and thereby the light emitted from the phosphor </li></ul><ul><li>13.Contact pins for cathode, filament and control electrode </li></ul><ul><li>14.Wire for anode voltage </li></ul>
  51. 51. CRT cont…. <ul><li>The electron beams are controlled by the focus control coil and the deflection coil . </li></ul><ul><li>This enables the electron beams to be focused on to a specific location of the phosphorus screen. </li></ul><ul><li>The mixture of the colors red, green and blue can create any given color. </li></ul>
  52. 52. CRT cont….. <ul><li>The electron beam scans the screen horizontally and vertically at a given number of times per second. </li></ul><ul><li>It also known as Refresh rate. </li></ul><ul><li>Higher refreshing rate making better views. </li></ul><ul><li>CRT monitors are high electricity consumption. But better display quality. </li></ul><ul><li>But also output lot of radiation that cause health issues. </li></ul>
  53. 53. Flat-Panel <ul><li>The most common type of Flat-Panels are LCD. </li></ul><ul><li>The LCD was first used in digital calculators and wrist-watches etc….. </li></ul><ul><li>And usually worked in monochrome (one color) </li></ul>
  54. 54. LCD <ul><li>LCD Stands for Liquid Crystal Display. </li></ul><ul><li>As the name amplifies the LCD screen is a grid of liquid crystals. </li></ul>
  55. 55. LCD cont….. <ul><li>By coloring all the pixels on screen an image is created. </li></ul><ul><li>The Refresh rate of LCD very similar to CRT monitors. </li></ul><ul><li>Originally designed for the Laptops but now a days also use within desktops. </li></ul><ul><li>Most modern day color display mobile and smart phones, PDAs, Digital and video cameras, portable DVD players and many more digital devices useLCD technology for the display. </li></ul>
  56. 56. LCD <ul><li>The main advantages of the LCD over CRT, that has a flat screen, </li></ul><ul><ul><li>Consumes very little space </li></ul></ul><ul><ul><li>Has better color quality </li></ul></ul><ul><ul><li>Consumes about 5% of the power </li></ul></ul><ul><ul><li>Used by a CRT, has low glare and produces no radiation and little heat. </li></ul></ul><ul><li>The main disadvantages of LCD, </li></ul><ul><ul><li>requires a special back-light </li></ul></ul><ul><ul><li>Has low contrast </li></ul></ul><ul><ul><li>Has a limited viewing angle </li></ul></ul><ul><ul><li>More expensive </li></ul></ul>
  57. 57. Other monitor types <ul><li>Some of the less common monitors are, </li></ul><ul><ul><li>ELD </li></ul></ul><ul><ul><li>Plasma </li></ul></ul><ul><ul><li>Paper-White </li></ul></ul>
  58. 58. ELD <ul><li>ELD Stands for Electro luminescent displays. </li></ul><ul><li>Similar to LCD. </li></ul><ul><li>But instead of liquid crystal phosphorus film sandwiched between two layers of film. </li></ul><ul><li>The advantage of this is that these have higher contrast and brightness and do not require a back light. </li></ul>
  59. 59. Plasma Display <ul><li>Plasma displays differ from LCD and ELD by, create the screen output use Gas in between layers of the screen. </li></ul><ul><li>Expensive method but can create high quality output and back light is not a requirement . </li></ul><ul><li>The screen size can be increase up to very higher level. </li></ul>
  60. 60. Paper-White displays <ul><li>These monitors are used by individuals who create high quality graphics like graphic designers for advertisements newspaper, and magazine and desktop publishers. </li></ul><ul><li>The display output is monochrome. That displays characters in black against a white background. Such monitors are popular for desktop publishing. </li></ul>
  61. 61. Key features of monitors <ul><li>A good monitor will be easy on your eyes and allow you to work for longer periods of time with comfort. </li></ul><ul><li>A bad monitor will cause eye strain and in the long run could harm your eyes. </li></ul><ul><li>When buying a computer there are some considerations. </li></ul>
  62. 62. Main features of monitor <ul><li>The size of the viewing area-usually stated in inches diagonally. </li></ul><ul><li>Resolution-the total amount of pixels of the screen. </li></ul><ul><li>Image contrast-The contrast between colors. </li></ul><ul><li>Image brightness-The brightness of the display. </li></ul><ul><li>Power consumption and management-The amount of power it uses and its power management features. </li></ul><ul><li>Refresh rates - the number of times a second it refreshes the screen </li></ul><ul><li>Price-up to the user. </li></ul>
  63. 63. Multimedia Projectors <ul><li>Use to share video output among large number of people. </li></ul><ul><li>Mainly there are two types of Projectors available, </li></ul><ul><ul><li>DLP </li></ul></ul><ul><ul><li>LCD </li></ul></ul>
  64. 64. DLP-Digital Light Processing <ul><li>These have a special microchip called the Digital Micro-mirror device. </li></ul><ul><li>The images projected by the DLP projectors are sharp not blur and brighter. </li></ul><ul><li>Can be use within normal light conditions. </li></ul><ul><li>Little time taken to cool down and compact in size. </li></ul><ul><li>But very expensive. </li></ul>
  65. 65. LCD-Liquid Crystal Display <ul><li>The projector lamp is shone through a LCD display with the image. </li></ul><ul><li>These projectors are not that bright therefore require a dark room. </li></ul><ul><li>The output quality is less compare to DLP projectors. </li></ul><ul><li>Also more time taken to cool down. </li></ul><ul><li>But the prize is low. </li></ul>
  66. 66. Sound Systems <ul><li>To get sound output from the computer system. </li></ul><ul><li>The soundcard and speakers have become a standard component in a computer system. </li></ul><ul><li>The soundcard converts the digital audio data in to an analog form during playback. </li></ul>
  67. 67. Sound Systems cont….. <ul><li>During recording the sound card converts the analog signal in to digital data and stores it on the disk. </li></ul><ul><li>To get sound outputs sound card have to attach with high quality speakers as well. </li></ul>Sound Card
  68. 68. Sound Systems cont….. <ul><li>For better quality outputs users can select necessary speaker systems. </li></ul>2.1 sound System 4.1 Surround sound System 7.1 Surround sound System 5.1 Surround sound System Headphones Stereo Speakers
  69. 69. Printers <ul><li>The printer is the device that provides you with a hardcopy output. </li></ul><ul><li>Printers are generally categorized in to two types, </li></ul><ul><ul><li>Impact - make a high impact on the printing paper, use pins or shapes to make the impact. </li></ul></ul><ul><ul><li>Non-impact – make low impact on the printing paper, but the ink will be spayed on the paper </li></ul></ul>