How Computer Monitors Work

By: Jeff Tyson & Carmen Carmack

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 screen displays) are replacing the venerable CRT on most desktops.


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.