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Computer ed.

Computer ed.






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    Computer ed. Computer ed. Presentation Transcript

    • Output: The Many Uses of Computers and Communications Audio, Video, Virtual Reality and Robots Outputs Types of Printers and Plotters Video Display Adaptors Types of Display Screens
    • Output devices translate information processed by the computer into a form that humans can understand. Several Types of Output Devices -Display Screens -Video-output devices -Printers and Plotters -Virtual-reality devices -Audio-output devices -Robots
    • Principal Kinds of Outputs Hardcopy – refers to printed outputs Softcopy – refers to data that is shown on a display screen or is in audio or voice form .It is not tangible.
    • Examples of Hardcopy - text or graphics printouts - film( microfilm, microfiche) Examples of Softcopy -Virtual reality -Robot
    • Display Screens: Softcopy Output
      • It is also called monitors
      • Output devices that show programming instructions and data as they are being input and information after it is processed.
    • Types of Display Screens
      • Cathode – Ray Tubes ( CRTs)
      • Flat Panels Display
    • Cathode – Ray Tubes ( CRTs)
      • The most common form of display screen.
      • It is a vacuum tube used as a display screen in a computer or video display terminal.
    • Flat Panel Displays
      • Much thinner, weigh less and consume less power than CRTs.
      • It is better for portable computers.
      • Made up of two plates of glass with a substance between them which is activated in different ways.
      • Example. LCD
    • Liquid – Crystal Display
      • Consists of a substance called liquid crystal, the molecules of which line up in a way that alters their optical properties.
    • Flat panel screens are either active – matrix or passive matrix displays. Active –matrix Display – each pixels on the screen is controlled by its own transistor. It is much brighter than passive –matrix but they are more complicated and expensive. Passive- matrix Display - a transistor controls a whole row or column of pixels .It is less expensive and use less power than active – matrix.
    • Pixels
      • Individual dots or picture elements that represented the images.
      • It is the smallest unit on the screen that can be turned on and off by the computer or made different shades.
      • Example of AMLCD
      • Example of PMLCD
    • Screen Clarity
      • Whether CRTs or flat-panel display, screen clarity depends on three qualities:
      • - Resolution
      • - Dot Pitch
      • - Refresh Rate
    • Resolution
      • The clarity of sharpness of a display screen.
      • The more pixels there are per square inch, the better the resolution.
      • It is expressed in terms of the formula horizontal pixels x vertical pixels
    • Dot Pitch
      • -The amount of space between the centers of adjacent pixels.
      • The closer the dots, the crisper the image.
      • for crisp images, dot
      • pitch should be less
      • than .31 millimeter.
    • Refresh Rate
      • The number of times per second that the pixels are recharged so that their glows remains bright.
      • Produced more clarity
      • and richer colors.
      • Displays are refreshed
      • 45 to 100 times per
      • second.
    • Monochrome versus Color Screens
      • Monochrome Display screens
      • - It displays only two colors.
      • -Usually black and white, amber and
      • black, or green and black
    • Color Screens
      • It can display between 16 and 16.7 million colors ( depending on their type )
    • Text versus Graphics: Character Mapped versus Bitmapped Display
      • Character mapped display screens
      • display only text – (letters,
      • numbers and special characters).
      • They cannot display graphics
      • unless a video display adapter
      • card is installed.
    • Bitmapped
      • - It permits the computer to manipulate pixels on the screen individually rather than as blocks.
      • It enables the software to
      • create a greater variety of
      • images.
    • Video Display Adapters
      • A display screen must have a video display adapter to display graphics.
      • It is also called a graphics adapter card.
      • It is a circuit board that determines the resolution, number of colors, and how fast images appear on the display screens.
      • It is often built into the motherboard and also be an expansion card that plugs into an expansion slot.
    • Video Display Adapter Standards
      • VGA – Video Graphics Array
      • - Most common video
      • standard.
      • - It support 16 to 256
      • colors.
    • SVGA – Super Video Graphics Array
      • It will support 256 colors at higher resolution than VGA.
    • XGA – Extended Graphics Array
      • It supports up to 16.7 million colors at a resolution of 1024 x 768 pixels.
      • - video display adapters
      • and monitors must be
      • compatible.
      • - computer software
      • and video display
      • adapter must be
      • compatible
    • Printers and Plotters: Hardcopy Output
      • Printer – is an output device that prints characters, symbols and perhaps graphics on paper.
      • - Impact Printers
      • - Nonimpact Printers
      • - Portable
      • - Combined with a PC
    • Impact Printers
      • It has a mechanisms resembling those of a typewriter.
      • It forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon leaving an image on paper.
      • Example: Dot-matrix printers
    • Dot- matrix Printer
      • Draft Quality
      • Near letter Quality
      • Advantages
      • Inexpensive
      • Can print multipart forms
      • Low cost per page
      • Disadvantages
      • Noisy
      • Cannot produce high quality output of text and graphics
      • Limited fonts.
    • Non-impact Printers
      • It is faster and quieter than impact printers because they have fewer moving parts.
      • It forms characters and images without making direct physical contact between printing mechanism and paper.
      • -Types:
      • Laser Printer, Inkjet Printer, Thermal Printer
    • Laser Printer
      • - Similar to a photocopying machine.
      • It uses the principle of dot-matrix printer in creating dot-like images.
      • However, these images are created on a drum, treated with a magnetically charged ink-like toner (powder) and then transferred from drum to paper.
      • Its typical speed is 8-200 pages per minute.
      • Its approximate cost is $400-$20,000.
      • Advantages
      • Quiet
      • Excellent Quality
      • Output of text and graphics
      • Very high speed
      • Disadvantages
      • - High Cost, especially for color.
    • Inkjet Printer
      • Can also form images with little dots.
      • It spray small electrically charged droplets of ink from four nozzles through holes in a matrix at high speed onto paper.
      • Even quieter than laser printer and produce an equally high quality image.
      • Its typical speed is 35-400+ characters per second.
      • Its approximate cost is $200-$2000.
      • Advantages
      • Quiet
      • Prints color text and graphics less expensive
      • Fast
      • Disadvantages
      • Relatively slow; clogged jets; fewer dots per inch
    • Thermal Printer
      • -It can produce high quality color printing.
      • -It used colored waxes and heat to produce images by burning dots onto special paper.
      • -Its typical speed is 11-80character per second.
      • -Its approximately cost is $2000-$22000.
      • Advantages
      • Quiet
      • High quality color output of text and graphics
      • Can also produce transparencies
      • Disadvantages
      • Special paper
      • required
      • Expensive
      • Slow
    • Black and White versus Color Printers
      • Impact printers are still needed however the choice between a laser printer and an inkjet comes down to how much you print and whether you need color.
    • Plotters
      • It is a specialized output device designed to produce high quality graphics in a variety of colors.
      • Especially useful for creating maps and Architectural drawings, although they may also produce less complicated charts and graphs.
      • The three principal kinds of plotters are pen, electrostatic and thermal
    • The Paper Glut: Whither the Paperless Office
      • Supposedly, computers were going to make the use of paper obsolete, providing us with “paperless office” but in fact the opposite happened.
    • The Theater of output: Audio, Video, Virtual reality and Robots
      • Audio Output Devices
          • It includes voice output technology and sound output technology
          • It includes those devices that output voice or voice like sounds and those that output music and other sounds.
      • Voice Output Devices
              • Convert digital data into speech like sounds
              • These are such forms of voice outputs on telephones, machines, in cars in toys and in other devices.
      • Sound Output Devices
              • Produce digitized a sound, ranging from beep and chirps to music.
    • Video Output Devices
          • It includes videoconferencing and digitized television.
      • Videoconferencing and Video Editing
            • Videoconferencing is a method whereby people in different geographical locations can have a meeting and see and hear one another using computers and communications.
    • HDTV or ATV
            • High Definition television is a television system that features enhanced video and clear pictures. (Far superior to any seen on television today, appearing within a frame that is twice as wide.
            • Because the new system surpassed all expectations, The Federal Communication Commission gave it a new name. Advanced Television (ATV).
            • In place of analog channel, it can transmit not just one high definition image but five or six digital channels as good as current ones.
    • Virtual Reality and Simulation Devices
      • Virtual Reality (VR) is a kind of computer generated artificial reality that projects a person into a sensation of three dimensional spaces.
    • To achieve this effect, the following interactive sensory equipments are needed.
      • Glove – has sensors that collect data about your hand movements.
      • Software – gives the wearer of this special headgear and glove the interactive sensory experience that feels like an alternative to the realities of the physical world.
    • Simulators are devices that represent the behavior of physical and abstract systems.
    •   Robot is an automatic device that performs functions ordinarily ascribed to human beings or that operates with what appears to be almost human intelligence.
    • Creative Output: The Manipulation of Truth in Art and Journalism
      • The ability to manipulate digitized output-images and sounds – has brought a wonderful new tool to art. However it has created some big new problems in the area of credibility.
      • Manipulation of Sound
      • Manipulation of Photos
      • Manipulation of Video