In older CRT monitors and TVs, magnetic charges would build up inside them causing a loss of color accuracy. To fix this problem, displays were equipped with a degauss function which, when used, would discharge this magnetism. Most sets would automatically degauss when they started up, which you would notice as a thunk or a hum when the set turned on. New flat-panel LCD monitors do not have a degauss function because magnetism does not build up in them.
- By Lowell Heddings on 07/30/12