Discharge in GasesYou can also watch our video about discharge in air at atmospheric pressure and at reduced pressure here: If you opened this page, I am sure you will love the site bellow: At right a Jacobs ladder discharge in air at atmospheric pressure together with a commercial "plasma lamp", based on Tesla's discovery of high frequency discharge. Bellow, a set of Geissler tubes as usually are provided for
the demonstration of discharge in rare gases. In the Geissler
tubes the pressure of the gas is high enough to allow ionized
atoms to collide with neutral atoms many time during their movement
between anode and cathode. The collided atones become excited
and emit a particular color radiation. Three of the tubes above "fired":
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Argon |
Neon |
 Krypton |
Below a totally different thing: moving electrons |
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In the tube at right, the vacuum is pretty high. An induction coil feeds unidirectional pulses. The residual gas pressure is low enough so that no collusion take place and the ionized atoms travel undisturbed from (+) to (-). At the cathode the collusion transfer the energy to the electrons trapped under the double layer and "frees" them. Their trajectory is observed with a phosphorescent screen. The modern electronics start here |
Bellow another Crooks tube (the tubes with pretty high vacuum): the paddle wheel. Again, not too much collision take place (cross-section small) between ions and atoms. However when the paddle wheel is hit, the phosphorus there brightens up. The atoms in vicinity heats up making the paddle to move. |
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