Re: tlug: degauss

["A.Tomita,Jr." <alberto@example.com>]

At 18:32 97/12/20 +0900, you wrote:
> What is it, and would it have anything to do with a monitor turning
> purple (as one of mine now does if it's on too long)?

The short answer is yes, by degaussing a monitor you eliminate the
color mismatches caused by the earth's magnetic field.

Now the long answer: degaussing means demagnetizing, and usually it
is done to eliminate residual magnetism induced in a magnetic material
(like the coils in the heads of tape cassete decks).

"Degaussing a monitor" means creating a magnetic field to demagnetize
the metal of the mask of the monitor (any one. either Trinitron or 
Shadow Mask, as they both are made of metal). It becomes magnetized
by induction from earth's natural magnetic field, and if the mask's
magnetic field becomes too strong (after a long period of time, if the
monitor is moved, or if there are other generators of magnetic fields
nearby), it starts to deflect the trajectory of the electrons, causing
misconvergence (impurities in the colors are due to a electron aimed
at R been deflected and hitting G or B, for example).  
 
Degaussing done by using a degaussing coil, that generates a magnetic
field with polarity inverse to earth's field, so the sum of the two
fields becomes zero. This degaussing coil is activated once when the
monitor is turned on, and whenever necessary by pressing the degauss
button.


---
A.Tomita,Jr.   atomita@example.com
               atomita@example.com

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