Is it possible for electricity to jump a vacuum gap?

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Discussion Overview

The discussion centers around the possibility of electricity jumping a vacuum gap, exploring the mechanisms and terminology associated with this phenomenon. Participants reference historical and practical applications, particularly in vacuum tubes and related technologies.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions whether electricity can jump a vacuum gap and seeks clarification on the terminology used.
  • Another participant asserts that it is possible, referencing Fleming tubes and mentioning arcing or conduction as potential mechanisms, depending on current and onset speed.
  • A historical context is provided by a participant who notes that vacuum tubes, used in radios and TVs, rely on electron flow.
  • Further elaboration includes the concept of thermionic emission and plate current in vacuum tubes, with a mention of the visibility of current and the heating of plates.
  • One participant introduces the idea of field emission of electrons under high electric field gradients in a vacuum, noting the production of x-rays when accelerated electrons collide with surfaces.

Areas of Agreement / Disagreement

Participants express varying perspectives on the mechanisms by which electricity can jump a vacuum gap, with no consensus reached on specific terms or conditions under which this occurs.

Contextual Notes

There are references to specific voltage thresholds and conditions for arcing and conduction that may depend on various factors, including the vacuum quality and electric field strength. The discussion does not resolve these technical details.

Who May Find This Useful

This discussion may be of interest to those studying electrical engineering, physics, or the historical development of electronic components, particularly vacuum technology.

mcjosep
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Is it possible for electricity to jump a vacuum gap? If so, what is it called when that happens?
 
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Yes. Otherwise those old Fleming tubes wouldn't work...
Arching or conduction depending on the amount of current and suddenness of onset.
It takes more voltage to get it going since air and moisture make better conduction paths. I seem to remember 30Kv/inch for an electrical arc in a vacuum, but I could be way off.
 
Before transistors, radio and TV sets used vacuum tubes, which are based on electron flow.
 
mcjosep said:
Is it possible for electricity to jump a vacuum gap? If so, what is it called when that happens?
In vacuum tubes, the electron current is called thermionic emission and plate current. The current is not visible, but the plates sometimes turn red hot.

With very high electric field gradients in very vacuum, field emission of electrons is possible, with lots of x-rays as the accelerated electrons hit the other side.

Bob S
 

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