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low power degaussing coil

Discussion in 'Electronic Repair' started by Tim Worthington, Feb 20, 2005.

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  1. I've got a small 5" colour monitor that I'm using a test monitor. It
    came with a small degaussing coil but no associated electronics.

    This monitor will be moved around a lot and I don't want to have to
    degauss it with a degauss wand every time it gets a bit magnitised. So
    i'm trying to think of a way to power the coil it already has.

    I'm thinking about putting a posister, the coil and a degauss button
    in series with the 240v mains available inside the box. What type of
    posistor to use? I imagine most would let too much current through
    before getting hot enough.

    Philips seem to have a large selection (availabe as tv spares) but I
    can't find specs anyware online...

    The coil is 140mm in diameter and has a DC resistance of 8 ohms

    any ideas?
     
  2. Can't help with specs but all degaussing coils inside TVs and monitors
    have a very low resistance and depend almost entirely on the Posistor
    for current limiting to a safe value and of short duration.

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  3. Phil Allison

    Phil Allison Guest

    "Tim Worthington"

    ** You need a bit more than that - usually a hefty relay is used to engage
    the posistor circuit with a timer to hold it on for 5 seconds or so. The
    button just initiates the timing cycle.


    ** De-gaussing coil current peaks at around 30 - 50 amps.


    ** Maybe just find an old PC monitor and remove one from it. But do not
    just fit a simple on-off button or you will end up magnetising the tube very
    badly.




    ............. Phil
     
  4. Guest

    I have Sanyo TVs built over 20 years ago that use nothing but a
    posistor in series with the degaussing coil.
     
  5. Phil Allison

    Phil Allison Guest


    ** TVs are nearly all like that.

    However, the OP has a portable monitor that may need to be de-gaussed
    whenever it is moved about.

    Hence the need for a "de-gauss" button.





    .............. Phil
     
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