Covering Monitor Basics


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Tutorial Home >Music and Video >Digital Music >Digital Hardware Requirements >Using Screens and Monitors >Covering Monitor Basics

  Step 1:  What Is the CRT Screen?

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Most monitors, as well as most televisions, use CRT screens. CRT is an acronym for cathode ray tube. This is a glass enclosure with electron "guns" that shoots electrons at the glass panel on the front that serves as the actual screen.
  Step 2:  How Electron Becomes Picture

The electrons strike small dots or stripes on the screen composed of materials called "phosphors" that glow a specific color (red, green, or blue) when struck by a stream of electrons. Each "pixel" or "picture element" is composed of one dot or stripe that produces each color. So each pixel becomes a particular combination of red, blue and green that creates virtually any color, and at any given instant, they display the color that the pixel is supposed to represent for that one part of the picture.
  Step 3:  What Is the Scan Line?

Pixels are organized into scan lines. Each scan line has a given number of pixels. The number of pixels varies with cost, quality, and use of the monitor, but generally is at least 350 and usually no more than around 2,000. The electron beams are timed and targeted to strike each pixel one after the other from left to right. The intensity of the electrons varies as they strike the different colored spots for each pixel, and this produces the colors for each single line of the picture.
  Step 4:  How Scan Lines Form Pictures

The lines of phosphors repeat from top to bottom to cover the entire screen. There can be from 480 to over 1400 lines on various types of monitors. The electron guns starts at the top and scan across one line, then down to the next, and so on to the bottom. Each line's scan is precisely timed to produce one "slice" of the picture. When all the lines have been scanned and all the phosphor dots or stripes are glowing at the desired intensity, there is a picture (or at least half of a picture).