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MIT Physics Demo -- Magnetic Deflection of a TV Image

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An cathode ray tube (CRT) television is connected to a video camera. When a strong magnet is brought close to the television screen, the image becomes warped and discolored.

While many new televisions use flat screen technology, older CRTs produced images by firing electron guns (one red, one green, one blue) through the television body onto the back of the screen. When a magnet is brought close to the screen, it deflects the paths of the electron beams and distorts the picture. A strong enough magnetic field can even create a hole in the electron beams, causing a black spot on the picture.

This TV has been subject to many magnet encounters, which has permanently damaged the picture.

Comments (4)

I did this 12 years ago

Posted 1 year by Anonymous User

The process of eliminating magnetization on a CRT is called degaussing (the unit of measure of magnetic inductive force is the gauss, named for mathematician Karl Friedrich Gauss). Most modern CRTs today include built-in degaussing circuits. Some have a manual switch to activate the circuit, some do it automatically and some offer both as an option. The degaussing circuit uses a coil of wire to neutralize magnetic fields within the CRT.

Posted 11 months by Anonymous

Try this at home, kids.

Posted 1 month by Anonymous 00:00:22

Who needs the LHC when you have a horshoe magnet …

Posted 1 month by Anonymous 00:01:04

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July 11, 2008 16:51
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