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How Computer Monitors Work
2018-11-12

Because we use them daily, many of us have a lot of questions about our monitors and may not even realize it. What does "aspect ratio" mean? What is dot pitch? How much power does a display use? What is the difference between CRT and LCD? What does "refresh rate" mean?

In this article, HowStuffWorks will answer all of these questions and many more. By the end of the article, you will be able to understand your current display and also make better decisions when purchasing your next one. ­

Monitor Display Technology

Often referred to as a monitor when packaged in a separate case, the display is the most-used output device on a computer. The display provides instant feedback by showing you text and graphic images as you work or play.

Most desktop displays use liquid crystal display (LCD) or cathode ray tube (CRT) technology, while nearly all portable computing devices such as laptops incorporate LCD technology. Because of their slimmer design and lower energy consumption, monitors using LCD technology (also called flat panel or flat screendisplays) are replacing the venerable CRT on most desktops.

Two measures describe the size of your display: the aspect ratioand the screen size. Historically, computer displays, like most televisions, have had an aspect ratio of 4:3. This means that the ratio of the width of the display screen to the height is 4 to 3.

For widescreen LCD monitors, the aspect ratio is 16:9 (or sometimes 16:10 or 15:9). Widescreen LCD displays are useful for viewing DVDmovies in widescreen format, playing games and displaying multiple windows side by side. High definition television (HDTV) also uses a widescreen aspect ratio.

Resolution refers to the number of individual dots of color, known as pixels, contained on a display. Resolution is expressed by identifying the number of pixels on the horizontal axis (rows) and the number on the vertical axis (columns), such as 800x600. Resolution is affected by a number of factors, including the size of the screen.

As monitor sizes have increased over the years, display standards and resolutions have changed.

Common Display Standards and Resolutions 

  • XGA (Extended Graphics Array) = 1024x768

  • SXGA (Super XGA) = 1280x1024

  • UXGA (Ultra XGA) = 1600x1200

  • QXGA (Quad XGA) = 2048x1536

  • WXGA (Wide XGA) = 1280x800

  • WSXGA+ (Wide SXGA plus) = 1680x1050

  • WUXGA (Wide Ultra XGA) = 1920x1200

  • WQHD = 2560 x 1440

  • WQXGA = 2560 x 1600

  • QSXGA = 2560 x 2048

In addition to the screen size, display standards and resolutions are related to something called the aspect ratio. Next, we'll discuss what an aspect ratio is and how screen size is measured.


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