CRT

• The earliest and most widespread TV technology is the Cathode Ray Tube (CRT) display. These TVs utilize a vacuum tube that fires electrons onto a fluorescent screen to create an image. These sets are inexpensive compared to their flat panel cousins, but they have other drawbacks. They are large and bulky, which in turn limits their screen size. The largest CRT TVs cap out in the mid-30-inch range. CRT's have also become uncommon if not extinct in retail stores as manufacturers are focused on flat panel technologies.
  
  

Projection

• Several type of projection technology exist. There are front projects, which project a video image onto a white screen similar to the way movies are displayed in theaters. Rear projectors, on the other hand, are similar in appearance to CRT TV's and use a lamp inside the unit to project an image. Similar sets include LCD projection and DLP projection, which use different technologies to project the image. These TVs are large, starting at 50 inches and going up from there, but like CRT's are becoming less and less available.
  
  

LCD

• The first and most common flat panel technology is the LCD, or Liquid Crystal Display. LCD's make use of a fluorescent backlight to send light through a display of liquid crystals to create an image. These units have superior image quality compared to CRT and projection units, but have suffered in creating black levels to other types of technology. Screen sizes vary greatly for LCD's, from 15 inches to over 50, and they are relatively cheap when compared to other flat panel displays.
  
  

Plasma

• Plasma screens are similar in appearance to LCD's, but make use of phosphor gases to create an image. These units are heavier than LCD's because of the glass required to contain the gases and they also only come in larger sizes, with the smallest plasmas measuring around 40 inches. Plasmas also have superior color reproduction and motion displace compared to LCD's, but can suffer from burn-in if left on for too long.
  
  

LED

• The newest display technology is LED, or Light Emitting Diode. These displays are made up of red, blue, and green LED lights that combine to create an image. These units offer superior color reproduction compared to any other display technology. Like LCD's, these displays can come in a variety of sizes. Being the newest technology, they are quite expensive compared to other technologies.