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Cs chapter 3 Presentation Transcript

  • 1. BIT Semester 1 Computer Systems Chapter 3 Input and Output Devices
  • 2. Input Devices
    • The devices that are use to input ‘Data’ to the computer.
    • Most Common input devices of the computer are,
      • Keyboard
      • Mouse
  • 3. Keyboard
    • The primary input device of the computer.
    • Using the keyboard you can do the simplest Input functions of entering data and commands to your computer system.
    • Has a similar layout to the typewriter.
    • but has some additional keys that provide additional functionality than a typewriter.
  • 4. Keyboard Cont….
    • Keyboards come in different shapes and sizes but may different the number of additional keys.
    • The keyboards may be connected to the computer system through a wire or as wireless.
    • 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.
  • 5. Keyboard Types
  • 6. Standard Keyboards
    • The standard keyboard has one hundred keys. This set of keys can be divided in to six categories.
      • Alphanumeric keys
      • Modifier keys
      • Numeric keypad
      • Function keys
      • Cursor-Movement keys
      • Special-purpose keys
  • 7. Alphanumeric keys
    • These include the alphabetical and numeric keys grouped together on the left side of the keyboard.
    • The main function of these keys is to simply enter what ever symbol that is displayed on the particular key.
  • 8. Modifier keys
    • These keys are located on the bottom left and right corners of the grouping of the alphanumeric keys.
    • These keys include “Shift, ”Ctrl”, Alt”
    • Should use with another supporting key to modify. E.g.- Ctrl+C, Ctrl+V, Alt+F4
  • 9. Numeric keypad
    • These are the set of keys that are located at the right most end of your keyboard.
    • These help to enter numeric data faster that using the alphanumeric keys.
  • 10. Function keys
    • These are the keys located on the top most row of the keyboard and labeled F1toF12.
    • These keys are allocated certain functions by different applications. E.g-F1-Help
  • 11. Cursor-Movement keys
    • These cursor keys include the quad-directional arrows keys and the" Home, End, Page-up, Pagedown”keys are the movement keys.
  • 12. Special-purpose keys
    • Special keys usually located between the alphanumeric and number-pad keys which allow you to carry out special functions.
    • These keys are the “Insert (also known as the over write), Delete, Print screen, Scroll Lock, Pause and Esc”
  • 13. Special keyboards
    • According to the users requirements the keyboard structure radically changed.
      • 101-key enhanced keyboard
  • 14. 104-key Windows keyboard
    • Two Windows keys and One Application Key attached to the keyboard.
  • 15. Mac keyboard
    • Similar to 101-keyborad.
    • But specially use within Apple Mac O/S.
  • 16. Multimedia and Web-enabled keyboards
    • Enable you launch you multimedia players and control your media player.
    • Support Many media facilities.
  • 17. Ergonomic keyboards
    • The term “ergonomic” implies that’ something's designed to optimize human well-being, overall system performance and human comfort
  • 18. Pointer Devices
  • 19. Pointer Devices
    • Any location on the computer screen can be addressed by using X-Y coordinates.
    • Pointer devices as the name implies are used to point to specific location on the computer screen.
    • According to the movement of the device screen pointer moves.
  • 20. Mouse
    • The second most common input device (after keyboard) is Mouse.
    • The X-Y Position indicator for a display system was invented by Mr. Douglas Englebartin 1964.
    • This device was later
    • called the mouse.
  • 21. Mouse cont……
    • The mouse comprises of four parts.
      • A ball/roller or optical sensors that indicate the mouse motion.
      • Buttons and/or wheel that are used to make selections and scroll.
      • A housing that holds the above components and lets you move the mouse around
      • An interface to connect to the computer system.
  • 22. Ball Mouse
    • The Ball mouse uses a ball/roller.
    • 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.
    • The disadvantage of the ball mouse is that it gathers dust and trash ,which cause unreliable motion.
  • 23. Optical Mouse
    • The optical mouse uses a light and an optical sensor.
    • Advantages-
      • More reliable to perform smoother operations.
      • Light weight.
      • No dust problems.
  • 24. Mouse cont….
    • The mouse rolls on a flat surface.
    • The motion of the mouse is picked up by the sensors and passed through the interface to the computer system.
    • The system software decodes this motion data and appropriately moves the pointer on the computer screen.
    • The required task can be executed by clicking the mouse buttons.
  • 25. Mouse interface…..
    • The interface between the mouse and the computer system may be wired or wireless.
    • Wired connection by via PS/2 port or USB.
    • Wireless may use radio signal or IR.
  • 26. Trackball
    • The trackball works like an upside-down mouse. (Ball mouse)
    • The ball is on the top of the device where as the mouse ball is on the underside.
    • The mouse has to be moved around where as the trackball remains stationary.
    • All other functions are similar to mouse.
    • The best example is the use of a trackball in laptops where you do not have space for a mouse.
  • 27. Touchpad
    • The touchpad also known as Trackpad.
    • First invented at 1994.
    • This is a square area about 2 inches by 1.5 inches.
    • The finger is used to move around on the touchpad and this is similar to movement of a mouse-”Strike sensitive”.
    • Tapping the Touchpad is one way to give inputs or users can use provided buttons.
    • More common within ‘Notebook’ environments.
  • 28. Pen-Stylus
    • The stylus is used to write on a special pad or directly on the screen.
    • The pen is commonly used for data entry on PDAs, handheld computers, tablet PCs, smart phones and palmtops.
    • Clicking the mouse similar to tapping the screen or pad by using the “Pen”.
    • To enter characters using a ‘Virtual Keyboard’.
  • 29. Touch Screen
    • Is a display screen which has sensors or capacitive film to locate where the finger is touching the screen.
    • Act as a input as well as output device.
  • 30. Touch Screen cont….
    • These are commonly used in locations where using a mouse or keyboard is not feasible and an intuitive interface is required.
    • The buttons or icons on the screen can be pressed by the finger or a Pen.
    • Very popular in ATMs , point of sales, mobile phones
  • 31. Joystick and Game Pad
  • 32. Joystick and Game Pad cont…
    • Use to provide the gaming experience for the users with more entertainment.
    • By using these motion & sound becoming more and more realistic.
    • New devices connected via USB ports and users can very easily plug & play the device without using device drivers.
  • 33. Optical Devices
  • 34. Optical Devices
    • Optical devices use light to capture data and input it in to the computer system.
  • 35. Barcode readers
    • Barcodes are a set of dark lines that are used to uniquely identify an item or product.
    • Barcodes are found in many products. (most of the International products)
    • This is a convenient way of entering data by simply swiping the printed barcode under the barcode reader.
    • These emits trips of LASER light and the reflected image is picked-up by the light sensors.
    • The captured image is processed and the barcode is identified and passed on to the computer system as an alpha numeric value.
    • This value can be processed by the program and a suitable response can be executed.
  • 36. Scanners
    • Scanners are used to capture printed image in to an electronic format.
    • Hard-copy input can be stored within a computer as soft-copy by using a Scanner.
    • This is done by shining light on to the image and capturing the wave length of light reflected a teach point of the image.
    • The wave length at each position is plotted to a two dimensional array that creates an electronic image file.
    • This image file can be stored within the computer.
  • 37. The types of Scanners
    • There are two types pf Scanners.
        • -Flatbed -Hand-held
  • 38. Microphones
    • The microphone is the device used to input sound into the computer system through the soundcard.
    • The microphone aids in recording speech, communicating though voice and providing voice commands.
    • Communication can be achieved through voice overIP telephony and voice chat.
    • If your computer system has voice recognition software it can recognize your voice command and execute appropriate actions.
  • 39. Video Input
    • 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.
    • There are some types of Cameras,
      • Web camera
      • Analog video camera
      • Digital video camera (DV and DVD)
      • camcorder
  • 40. Web Camera
    • This type can be considered the most prehistoric type of video camera.
    • Where it captures the image and transfers it directly to the computer system.
    • Specially use within online video conferencing. (Cam-Chat)
    • The video quality was low comparing to the other cameras.
    • Not support to capture and transfer sound.
    • Now a days come up as a in built device with portable devices.
  • 41. Analog video camera
    • These can capture and store analog video on magnetic tapes.
    • These cameras also capture sound.
    • The main disadvantage is user need to have a special video capture card to convert the analog video in to digital format.
  • 42. DV Camera
    • The DV camera stores the audio and video on DV tapes in digital format.
    • Connect to the computer via “Fire-Wire” interface.
    • Fire-wire interface allow the control of the camera playback through a GUI on the computer system.
    • Disadvantage is data transfer time similar to recording time.
  • 43. DVD Camera
    • The DVD cameras directly write the video on to a mini-DVD/DVD.
    • These can be read using a DVD-ROM and copied to the computer using DVD-ripping software.
  • 44. Camcorder
    • 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.
    • 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)
    • File can be simply copy. (Don’t need to convert)
    • The video quality is very high.
    • Easy to use than other devices.
  • 45. Digital cameras
    • The difference between digital cameras and video cameras is that digital cameras only captures still images and store them in a digital memory card.
    • Most often the image file is compressed and stored on the memory card to allow a large number of photographs to be taken.
    • The memory card is displayed like another disk drive on your computer system when you connect the digital camera to the computer system.
    • Users just need to copy items. (Don’t need conversion method)
  • 46. Output devices
    • The computer uses output devices to transfer information to the environment and the user.
  • 47. Monitors
    • The primary output device of the computer system.
    • Monitors provide us with a graphical representation of information on the screen.
    • Mainly there are two types,
      • CRT
      • Flat-panel
  • 48. CRT
    • CTR stands for Cathode Ray Tube.
  • 49. CRT cont…..
    • This is the technology commonly used in television sets.
    • 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.
    • When the electron beam strike the coating it glows with the particular color.
    • The three electron beams are intended to glow the red , green and blue phosphors.
  • 50. CRT elements
    • 1. Deflection coils
    • 2. Electron beam
    • 3. Focusing coil
    • 4. Phosphor layer
    • 5. Filament for heating the cathode
    • 6. Graphite layer on the inner side of the tube
    • 7. Rubber gasket where the anode voltage wire enters the tube
    • 8. Cathode
    • 9. Air-tight glass "body" of the tube
    • 10.Screen
    • 11.Coil yoke made of iron
    • 12.Control electrode regulating the intensity of the electron beam and thereby the light emitted from the phosphor
    • 13.Contact pins for cathode, filament and control electrode
    • 14.Wire for anode voltage
  • 51. CRT cont….
    • The electron beams are controlled by the focus control coil and the deflection coil .
    • This enables the electron beams to be focused on to a specific location of the phosphorus screen.
    • The mixture of the colors red, green and blue can create any given color.
  • 52. CRT cont…..
    • The electron beam scans the screen horizontally and vertically at a given number of times per second.
    • It also known as Refresh rate.
    • Higher refreshing rate making better views.
    • CRT monitors are high electricity consumption. But better display quality.
    • But also output lot of radiation that cause health issues.
  • 53. Flat-Panel
    • The most common type of Flat-Panels are LCD.
    • The LCD was first used in digital calculators and wrist-watches etc…..
    • And usually worked in monochrome (one color)
  • 54. LCD
    • LCD Stands for Liquid Crystal Display.
    • As the name amplifies the LCD screen is a grid of liquid crystals.
  • 55. LCD cont…..
    • By coloring all the pixels on screen an image is created.
    • The Refresh rate of LCD very similar to CRT monitors.
    • Originally designed for the Laptops but now a days also use within desktops.
    • 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.
  • 56. LCD
    • The main advantages of the LCD over CRT, that has a flat screen,
      • Consumes very little space
      • Has better color quality
      • Consumes about 5% of the power
      • Used by a CRT, has low glare and produces no radiation and little heat.
    • The main disadvantages of LCD,
      • requires a special back-light
      • Has low contrast
      • Has a limited viewing angle
      • More expensive
  • 57. Other monitor types
    • Some of the less common monitors are,
      • ELD
      • Plasma
      • Paper-White
  • 58. ELD
    • ELD Stands for Electro luminescent displays.
    • Similar to LCD.
    • But instead of liquid crystal phosphorus film sandwiched between two layers of film.
    • The advantage of this is that these have higher contrast and brightness and do not require a back light.
  • 59. Plasma Display
    • Plasma displays differ from LCD and ELD by, create the screen output use Gas in between layers of the screen.
    • Expensive method but can create high quality output and back light is not a requirement .
    • The screen size can be increase up to very higher level.
  • 60. Paper-White displays
    • These monitors are used by individuals who create high quality graphics like graphic designers for advertisements newspaper, and magazine and desktop publishers.
    • The display output is monochrome. That displays characters in black against a white background. Such monitors are popular for desktop publishing.
  • 61. Key features of monitors
    • A good monitor will be easy on your eyes and allow you to work for longer periods of time with comfort.
    • A bad monitor will cause eye strain and in the long run could harm your eyes.
    • When buying a computer there are some considerations.
  • 62. Main features of monitor
    • The size of the viewing area-usually stated in inches diagonally.
    • Resolution-the total amount of pixels of the screen.
    • Image contrast-The contrast between colors.
    • Image brightness-The brightness of the display.
    • Power consumption and management-The amount of power it uses and its power management features.
    • Refresh rates - the number of times a second it refreshes the screen
    • Price-up to the user.
  • 63. Multimedia Projectors
    • Use to share video output among large number of people.
    • Mainly there are two types of Projectors available,
      • DLP
      • LCD
  • 64. DLP-Digital Light Processing
    • These have a special microchip called the Digital Micro-mirror device.
    • The images projected by the DLP projectors are sharp not blur and brighter.
    • Can be use within normal light conditions.
    • Little time taken to cool down and compact in size.
    • But very expensive.
  • 65. LCD-Liquid Crystal Display
    • The projector lamp is shone through a LCD display with the image.
    • These projectors are not that bright therefore require a dark room.
    • The output quality is less compare to DLP projectors.
    • Also more time taken to cool down.
    • But the prize is low.
  • 66. Sound Systems
    • To get sound output from the computer system.
    • The soundcard and speakers have become a standard component in a computer system.
    • The soundcard converts the digital audio data in to an analog form during playback.
  • 67. Sound Systems cont…..
    • During recording the sound card converts the analog signal in to digital data and stores it on the disk.
    • To get sound outputs sound card have to attach with high quality speakers as well.
    Sound Card
  • 68. Sound Systems cont…..
    • For better quality outputs users can select necessary speaker systems.
    2.1 sound System 4.1 Surround sound System 7.1 Surround sound System 5.1 Surround sound System Headphones Stereo Speakers
  • 69. Printers
    • The printer is the device that provides you with a hardcopy output.
    • Printers are generally categorized in to two types,
      • Impact - make a high impact on the printing paper, use pins or shapes to make the impact.
      • Non-impact – make low impact on the printing paper, but the ink will be spayed on the paper
  • 70.