Output devices

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Output devices

• Szabó Norbert

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Types of output devices

• Monitor
• Printer
• Speaker
• Plotter

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Monitors

• Its the most important output device
• 2 common types
• CRT
• LCD
• Featured by
• Refresh rate
• Resolution
• Visible screen size
• Response time

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CRT monitors

• This acronym stands for Cathode Ray Tube
• Very widespread
• Cheap
• Good performance

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Working method of CRT monitor

• The back of the tube has a negatively charged
  cathode, so called electron gun. The electron gun
  shoots electrons down the tube and onto a
  positively charged screen. The screen is coated
  with a pattern of red, green and blue phosphor
  dots that will glow when struck by the electron
  stream. The three dots together make up a pixel.

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LCD screens

• LCD means Liquid Crystal display
• Good quality
• Environment friendly
• (no lead in the glass)

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How it works?

• There is a thin liquid cristal layer between a
  horizontal and a vertical filter. Thanks to an
  appropriate voltage liquid cristals get arranged
  and light can pass the filters. This light will
  appear on the screen.
• In color LCDs each individual pixel is divided
  into three cells, or subpixels, which are colored
  red, green, and blue. Each subpixel can be
  controlled independently to yield thousands or
  millions of possible colors for each pixel.

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Printers

• A computer printer, or more commonly just a
  printer, is a device that produces a hard copy of
  documents stored in electronic form, usually on
  physical print media such as paper.
• In addition, many modern printers can directly
  interface to electronic media such as memory
  sticks or memory cards, or to image capture
  devices such as digital cameras, scanners some
  printers are combined with a scanners and/or fax
  machines in a single unit.

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Main types of printers

• Dot matrix
• Inkjet
• Laser
• Thermal

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Dot matrix printer

• A dot matrix printer or impact matrix printer
  refers to a type of computer printer with a print
  head that runs back and forth on the page and
  prints by impact, striking an ink-soaked cloth
  ribbon against the paper, much like a typewriter.
  Unlike a typewriter, graphics can be produced.

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Inkjet printers

• Inkjet printers are a type of computer printer
  that operates by propelling tiny droplets of
  liquid ink onto paper. They are the most common
  type of computer printer for the general consumer
  due to their low cost, high quality of output,
  capability of printing in vivid color, and ease
  of use.

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Laser Printers

• Laser printers are printer that uses laser
  technology to print images on the paper. These
  work in a manner similar to a photocopier. The
  laser recreates the image on a negatively drum. A
  roller is charged with electricity, then a laser
  is used to remove the charge from portions of the
  roller. Powdered ink (toner) sticks to the parts
  of the roller that were hit by the laser, and
  this toner is transferred from the roller to the
  paper. Then the ink is baked into the paper using
  a heater.

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Speaker

• Speakers allows the computer to display sound.
• There are built-in ones, but you can choose
  external types too. Its better, because it
  provides a better quality even can perform
  surround sounding which is the best choice for
  games and videos.

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Plotter

• A plotter is a vector graphics printing device
  that connects to a computer.
• Plotters print their output by moving a pen
  across the surface of a piece of paper. This
  means that plotters are restricted to line art,
  including text, but do so very slowly because of
  the mechanical movement of the pens. Plotters are
  used primarily in technical drawing where they
  have the advantage of working on very large paper
  sizes while maintaining high resolution.

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Happy end