voltage spawning a cathode ray

vanmaiden

In descriptions of the cathode ray, various sites mention how the ray is formed from a voltage applied to the tube which spawns the ray on sees in the vacuum tube. Could someone elaborate on how a voltage can spawn this beam? As in, where does the potential difference come from and so on.

Thank you

Drakkith

A "cathode ray" is simply an electron that has been emitted from the cathode and accelerated by the negative voltage applied. (Or a positive voltage from an anode) The electrons can be emitted through "thermionic emission" by heating the cathode, or a "cold cathode" can be used in which a very high voltage ionizes the remaining gas inside an evacuated vacuum tube.

http://en.wikipedia.org/wiki/Cathode_ray

vanmaiden

Thank you!