Is it possible for electricity to jump a vacuum gap?

Yes, it is possible for electricity to jump a vacuum gap. When this happens, it is called arching or conduction, depending on the amount of current and suddenness of onset. In vacuum tubes, it is known as thermionic emission and plate current. However, it takes more voltage to get it going since air and moisture make better conduction paths. The voltage required can vary, with some sources suggesting 30Kv/inch for an electrical arc in a vacuum. Before transistors, electronic devices such as radios and TVs used vacuum tubes, which rely on electron flow. With very high electric field gradients in a vacuum, field emission of electrons is also possible, resulting in the production of x-rays.
  • #1
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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  • #2
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.
 
  • #3
Before transistors, radio and TV sets used vacuum tubes, which are based on electron flow.
 
  • #4
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
 
  • #5


Yes, it is possible for electricity to jump a vacuum gap. This phenomenon is known as vacuum breakdown. In a vacuum, there are no particles present to carry the electricity, so it is unable to flow in the traditional sense. However, when a strong enough electric field is applied, it can cause the vacuum to break down and allow the flow of electricity. This can occur in high voltage systems and is an important consideration in designing and maintaining vacuum systems.
 

1. Can electricity jump a vacuum gap?

Yes, it is possible for electricity to jump a vacuum gap. This phenomenon is known as vacuum breakdown or vacuum discharge.

2. What is vacuum breakdown?

Vacuum breakdown is the sudden occurrence of electrical conduction through a vacuum or gas between two electrodes placed in close proximity to each other. It is a result of the buildup of an electrical field that exceeds the dielectric strength of the vacuum.

3. What is the dielectric strength of a vacuum?

The dielectric strength of a vacuum is approximately 30,000 volts per centimeter. This value can vary depending on factors such as temperature, gas composition, and electrode shape.

4. How does electricity jump a vacuum gap?

When a high enough voltage is applied across a vacuum gap, the electric field becomes strong enough to ionize the gas molecules within the gap. This creates a conductive path for the electricity to flow through, allowing it to jump the gap.

5. What are some practical applications of vacuum breakdown?

Vacuum breakdown has several practical applications, including in vacuum tubes, particle accelerators, and high-voltage switches. It is also used in vacuum arc remelting, a process for refining metals, and in vacuum interrupters for circuit breakers.

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