Output devices

Output devices

1. Dot Matrix

   • A print head consisting of a number of pins, moves back and forth on a cartridge
     • Cheapest and reliable
     • Slowest, noisiest

2. Ink jet

   • Controller receives information from the computer about what needs to be printed. Translated into a series of instructions that are sent to various elements of the printer
     • Cheap, reliable, good quality
     • Slow, cope less with bulk

3. Laser

   • Printer's processors prepare the received data and then send a series of instructions to the print head
     • Fast, reliable, high quality, quiet, handle bulk
     • Expensive, toner cartridges replaced regularly

4. Plotter

   • Specialised output devices that are used when precise, high definition copies are needed and are A1
     • Pen, least expensive, slow, limited functions
     • Ink jet, quiet, detailed
     • Electrostatic, very high resolution, faster, expensive chemicals

5. CRT

   • Special adapter converts computers digital signal to an analogue signal (DAC)
     • Size, more power, emit small amounts of electromagnetic radiation, heat
     • Cheap, quality of resolution and colours

6. LCD

   • Made of multiple layers, with each layer performing an improtant function. Light is emitted from a constant light source, passed through a polarised filter that allows only horizontal vibrations through
     • Light, adaptable, less space, digital cameras, palm tops, not as much energy
     • Has to be viewed face on, slower refresh rate (streaking), difficult maintaining image quality at competitive price for larger screens

7. LED

   • An LED display is a flat panel display, which uses light-emitting diodes as a video display
     • Better color reproduction, less energy, super thin, high color gamuts, more accurate colors
     • Very expensive, sometimes only used as a back light for TFT display

8. Speakers

   • An output device for handling sound. A speaker takes audio electrical signals and converts them into actual sound that people can hear
     • Simple, blind, alerts
     • More disc space, distraction

9. Resolution & Pixels

   • This means how many lines, pixels or dots are present over a standard length. Length is usually inches or millimetres
     • More pixels=better quality
     • High resolution displays are expensive

10. Drivers

    • Software that converts commands such as print into instructions for hardware to understand
      • Quick to connect, adapters aren't required
      • Needs to be updated

11. Spooling & Buffering

    • Form of memory which allows you to send your document to the printer and then go onto another piece of work/log off
      • Allows jobs to be queued up, increases efficiency
      • Difficult to know whether or not your job is being processed

12. Actuator

    • Device that moves something when commanded to do so
      • Can be very tiny, performs complex tasks
      • Expensive