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First, what do you call this in English?

http://www.dieter-heidorn.de/Physik/SS/K06_Elektrisches%20Feld/K01_Ladung_Strom/K11_Ladung/Ladung02.gif

Second, how does it work? Why do I have not only light at the gas barrier between the two wires?

Thanks!

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2 Answers 2

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This is a "glow lamp". This special form, btw, is no longer fabricated. Zur Arbeitsweise und und Grund für das Vorherrschen des negativen Glimmlichts google doch mal nach Glimmentladung.

http://de.wikipedia.org/wiki/Glimmentladung

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

Der deutsche Artikel ist wesentlich besser.

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But this don't really help me. Can you explain why I have light on only one side? Thanks! (lets speak english, also if I am German :) ) –  kame Feb 16 '11 at 14:47
    
This is why the lamp in the picture was driven with DC, that is all. That "skin" of light is always around the cathode only. –  Georg Feb 16 '11 at 14:55
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This is neon lamp. They are still in production, used for indication of mains power for example. Also, used for decoration - in the form of very long tubes.

They work by exciting gas at very low pressure using some 100-200V voltage. Color is different for different gases, almost any color is possible.

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But why not only light between the two wires? –  kame Feb 16 '11 at 14:47
    
"Neon lamp" is the poular name, and the "form of very long tubes" is something different, because those "neon sign" lamps are not operated in the domain of regular glow discharge. –  Georg Feb 16 '11 at 14:50
    
@kame: did You read the wikis meanwhile? –  Georg Feb 16 '11 at 14:50
    
i understand now :) Thanks! –  kame Feb 16 '11 at 15:31
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