Electron velocity versus voltage is easily calculated from the literature;
Yes, the velocity of electrons in a vacuum is easy to calculate as well as the velocity of electrons between the molecules of gas.
...but first I must know if you were even referring to this "intermolecular velocity".
As the HV between the cathode and anode accelerates the electrons between the atoms of the gas, the electrons accelerate and gain kinetic energy just as they would in vacuum, but as soon as they collide with a molecule of the gas
*, they give up that energy and speed (completely or partially), only to be accelerated again by the applied HV before they collide with another molecule. This acceleration followed by a collision happens iteratively over and over...
* As a result of this collision, the excited atoms of the gas can decay and emit light later, but that is a secondary phenomenonOn average, this stop & go motion of electrons is millions times slower than the collision-free motion of electrons through vacuum (or intermolecular space) and is called "drift velocity". This velocity eventually causes the electrons to reach the anode.
The drift velocity is
not easy to calculate in a gas ! ( see the attachment. )
I must know if you are referring to this "drift velocity" or to the "intermolecular velocity" in your proposition of the operating principle.
and yes it does depend to some extent on the environment but they do propagate.
Yes, it
depends very much on the environment (gas properties, pressure, temperature,
Td and the applied HV) because the more space there is between the molecules of gas, the more time the electrons have to accelerate before they collide again.
e.g. the lower the pressure of the gas, the more space there is between the molecules of gas and the electrons have more time to accelerate to higher velocities.
Sorry, not sure what the question is!
The question is very important and well defined:
In your proposition of the operating principle, did you refer to the "intermolecular speed" of the electrons or to the "drift velocity" of the electrons ?
Your concerns should be clear once the provided literature is digested.
I read it and the question stands.
What excites the florescence coating in a florescence tube...
UV photons which are emitted by the decaying atoms of gas inside the tube (
after the electrons collide with them, give up their kinetic energy and excite them).
Without a vacuum your heated cathode probably would not last long (burn up) but is it really necessary otherwise?
Heated cathode is not necessary for a gas to conduct electrons (e.g. see
CCFL or
EL) ...but it helps.
BTW: I never mentioned a heated cathode.
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Topic: Dally, Shark & Ruslan workbench (Read 309413 times)
