Monitors


	The Ins and Outs of Monitors

Created September 27, 2004

Monitor is a term that is used both for a display screen and a box like a television that displays computer output. They come in many types, shapes, sizes and qualities. Some of the types are:

LCD (liquid crystal display) - often used on laptops
CRT (cathode ray tube) - uses the same technology as a television. Used in most computer monitors
TFT (thin film transistor)
Multi scanning - monitors that automatically adjust to the frequency of the signals being sent to it. This means that they can display images at different resolutions, depending on the data being sent to them by the video card.

Some sizes:

Regular monitor - a big box with a rounded screen
Flat screen monitor - a big box monitor with a flat screen to reduce glare
Flat panel - a very thin display screen used in laptops. They are also sold singly for use with a desktop or tower computer.

Quality is affected by such things as screen size, resolution, the dot pitch, the refresh rate, and the video adapter (card).

Screen size - This is measured diagonally. Note that all monitors have a border area that cannot be used. Thus the viewable area size is what should be measured.
Resolution - This is a factor of the number of pixels, or dots of light that make up the basic picture element of the screen. Computer screens are made up of thousands (in very high resolution millions) of dots arranged in a series of rows and columns like a table with very small squares. As the number of dots per line increases, so does the resolution and the ability to create round circles and other shapes that are not perfectly square. The clarity of letters and other objects improves with the resolution. The terms below are used to denote this resolution. The numbers indicate the number of pixels on the screen, the first the horizontal, the second, the vertical.
- VGA -- 640 x 480 resolution
- SVGA -- 800 x 600 resolution
- XGA -- 1024 x 768 resolution
- SXGA -- 1280 x 1024 resolution
- UXGA -- 1600 x 1200 resolution
Dot pitch - this term refers to how much vertical distance there is between each pixel. The smaller the dot pitch, the sharper the image. If, however, the distance is too small the screen brightness and contrast will be lessened. On color monitors a range from 0.22 mm to 0.42 mm is seen. The 0.22 mm dot pitch gives a better picture.
Refresh rate - this determines how often the screen is redrawn. Measured in hertzes (Hz), any of the above monitors require that the screen be redrawn at least 75 times per second for a refresh rate of least 75Hz. A lower refresh rate will result in screen flicker.

For more information about monitors see "How Monitors Work" at: http://computer.howstuffworks.com/monitor1.htm

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The Ins and Outs of Monitors