Output Devices

Output Devices

An output device displays information on a screen, creates printed copies or generates sound. A monitor, printer, and speakers are examples of output devices.

Some Common Output Devices:

Monitors and Displays

• Shows the processed information on a screen
  • A monitor uses a Picture Tube like a television with the image displayed on the front of the tube, which is called the screen.
    
    
    
    
  • Displays are flat and use plasma, LCD, active-matrix, or some other technology.
    
    
    
• Monitors used to be called Cathode Ray Tubes (CRTs) because of the picture tube, which is a large vacuum tube.
• A monitor or display produce a soft copy. When the device is turned off the information goes away.
• Monitors are slowly being replaced by flat panel displays.
  

Printers

• Printers produce a hard copy
• The information is printed on paper and can be used when the device is off.
• It is also called a printout
• Dot-matrix printers (impact printer)
  
  
  
  
  • Uses metal pins to strike an inked ribbon to make dots on a piece of paper.
  • Can see the dots that make up the letters or images.
  • Lowest print quality of all of the printers.
  • Very low in cost per page to use.
  • Rarely used today because of the poor print quality, but still used in business to print multi-part forms.
    
    
• Ink jet printers (non-impact printer)
  
  
  
  
  • Use drops of magnetic ink to produce dots on a page to produce text or images.
  • The print quality is almost the same as a laser printer's.
  • Problems with the ink
    • The ink is very expensive
    • The ink is water soluble and will run if the paper gets wet
  • Highest cost per page of all the printers
  • For producing color documents, it has the highest quality at a reasonable price.
    
    
• Laser printers (non-impact printer)
  
  
  
  
  • How the laser printer produces an image
    • A laser or LEDs make dots on a light sensitive drum
    • Toner (very tiny particles of plastic) stick to the drum where the dots where made
    • Paper is pressed against the drum and the toner is placed on the paper
    • The paper is heated and the toner melts into the paper
  • Produces the highest quality printout
  • For black and white printouts, very low cost per page
  • Printout is permanent
  • Color laser printers are still fairly expensive ($3,000 to $10,000)

Speakers

• used to output sound