The question often arises: Well, if magnetization and the need for degauss is a problem, why not make the shadow mask or aperture grille from something that is non-magnetic?
The shadow mask *must* be made of magnetic material! This may seem to be undesirable or counterintuitive but read on: Together with the internal shielding hood it forms sort of a closed space in which it is attempted to achieve a field-free space. The purpose of degaussing is *not* to demagnetize the metal, but to create a magnetization that compensates for the earth’s magnetic field. The *sum* of the two fields must be near zero! Degaussing coils create a strong alternating magnetic field that gradually decays to zero. The effect is that the present earth magnetic field is “frozen” into the magnetic shielding and the field inside the shielding will be (almost) zero. Non-zero field will cause colour purity errors. Now you will understand why a CRT must be degaussed again after it has been moved relative to the earth’s magnetic field. This will also explain why expensive computer monitors on a swivel pedestal have a manual degaussing button, you must press it every time after you have r
Related Questions
- The question often arises: Well, if magnetization and the need for degauss is a problem, why not make the shadow mask or aperture grille from something that is non-magnetic?
- Why is the Shadow Mask or Aperture Grill Made of a Magnetic Material?
- Whats the difference between a shadow mask vs. aperture grille?
