#Cathode ray tube monitors tv#

Sometimes, often after repeated cycling, the TV will fail to degauss.

If the distortion and colours remain after taking the magnet away from the TV, turning it off and on again should force the TV to ‘degauss’ which will fix the problem-this is signified by the distinctive clunk which often accompanies a CRT turning on.

The image will warp, and sweeping trails of colour will appear.

Put the strong magnet near to the TV screen.

A relatively still, bright image or video makes the effect we’re about to observe easier to distinguish. For a TV, many camcorders and digital stills cameras will have an S-video, component or composite connection older camcorders may have these directly, but newer camcorders or digital cameras may have a bespoke cable which plugs into a mini-USB or similar jack on the camera and feeds out to multiple types of connector for insertion into the TV. If it’s a computer screen simply plugging it into a laptop should work.

Get an image on the television or computer screen.

Apply a higher magnetic field to demonstrate that the curvature can again be increased by increasing the magnetic field strength.

Having curved the path of the beam, turn up the energy further and show that the curvature decreases with increasing electron energy.

If your CRT does have Helmholtz coils, turn up the current in them until the beam bends.

You may need to do this quite slowly if the camera is set to a low frame rate to increase its low light sensitivity.

If your CRT doesn’t have Helmholtz coils, simply wave the neodymium magnet near the CRT to show the beam bending.

Turn up the energy of the electron beam until the gas inside the globe is clearly glowing.

Dim the lights and turn on the camera if you’re using one.

If you’ve not got a cathode ray tube, an old CRT TV or computer monitor and a strong magnet will provide a more qualitative version of this demo.

#Cathode ray tube monitors manual#

The beams of electrons are too dim for anything except a very small audience to see directly, and are something of a challenge for video equipment too! A camera with a night mode, or manual control over gain (or ISO) and shutter speed will probably be necessary. In addition to a cathode ray tube, you’ll probably need a sensitive camera to show your audience the results of this experiment. In the absence of Helmholtz coils, a strong neodymium magnet should suffice to bend the electron beam.

The ideal CRT is enclosed by Helmholtz coils to allow a varying magnetic field to be applied. This experiment obviously requires a cathode ray tube filled with gas which glows when electrons hit it.