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 Post subject: Electron Tube
PostPosted: May Thu 02, 2019 6:03 pm 
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Electron Tube. that would make you think electron flow

https://scontent-mia3-2.xx.fbcdn.net/v/ ... e=5D753E09

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Last edited by tubeAMP on May Thu 02, 2019 8:04 pm, edited 2 times in total.

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 Post subject: Re: Electron Tube
PostPosted: May Thu 02, 2019 7:02 pm 
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Link doesn't open.

Sorry, this content isn't available right now
The link you followed may have expired, or the page may only be visible to an audience you're not in.


Dave


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 Post subject: Re: Electron Tube
PostPosted: May Thu 02, 2019 8:03 pm 
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sorry try the new image


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 Post subject: Re: Electron Tube
PostPosted: May Thu 02, 2019 10:55 pm 
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I must be missing something...


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 Post subject: Re: Electron Tube
PostPosted: May Thu 02, 2019 11:13 pm 
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That's exactly what it does, electrons flow through it, sort of the whole concept of how electricity works.


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 12:46 am 
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What's the question?

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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 12:58 am 
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some believe that electrons do not flow :P

by definition current is the flow of electrons or is it :shock:


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 1:25 am 
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tubeAMP wrote:
some believe that electrons do not flow :P

by definition current is the flow of electrons or is it :shock:

Current could also be the flow of holes.


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 1:33 am 
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yes the absence of an electron is a hole. the virtual hole flow in the opposite direction. some say that this is current the same direction as the arrows in a circuit. so how would you go about measuring the direction of current ? detect the flow direction ?


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 2:03 am 
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You measure current by passing it thru a known resistor, measuring the voltage across the resistor, and applying Ohm's law.

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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 2:32 am 
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It was Edwin Hall ("Hall" effect) that determined that the principle charge carriers in metal conductors are negative. This was in 1879, 18 years before the discovery of the electron.
From Hall Effect on Wikipedia:
One very important feature of the Hall effect is that it differentiates between positive charges moving in one direction and negative charges moving in the opposite. The Hall effect offered the first real proof that electric currents in metals are carried by moving electrons, not by protons.


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 3:10 am 
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Yes, in the "electron tube" its the electrons flowing.

The confusion, if there is any, seems to stem from "conventional current," i.e. current 'flow' from positive to negative.

When Franklin proposed the notion that electricity 'flowed' he envisioned a fluid, like water in a river, and he had to pick a direction for the 'flow'. His idea was that 'current' 'flowed' from a surplus region, which he called "positive", to a region with less, which he called "negative." As luck would have it, with a 50-50 chance of getting it right, he rather arbitrarily picked the opposite.

When it was later discovered that the charge carrier was the electron it then became, out of necessity, "negatively charged" (if Franklin had chosen the reverse nomenclature the electron would be called a positive charge and everything would be polarity reversed) and current was really flowing from an 'excess' of these negatively charged things to the 'positive' region where there were fewer.

By that time, however, 'electric flow' was well established practice so its called "conventional current" to distinguish the naming convention from 'reality'.

Of course, it's now known that the electron isn't the only possible 'charge' nor the only 'charge carrier'.


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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 11:37 am 
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......are the holes negatively charged, or positively charged? Can a hole actually flow? If so, is it the whole hole, or just part of the whole?

ok I'm going back to bed, or get more coffee now .....

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 Post subject: Re: Electron Tube
PostPosted: May Fri 03, 2019 5:01 pm 
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in the absence of an electron a copper atom would become a positively charged ion easily accepting another free electron. we know that a positively charged vacuum tube plate attracts free electrons. is this a measure of the direction of current flow? an ammeter detects current but in what direction?


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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 6:17 am 
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Greetings to the Forum:

Get yourself a Chinese Checkers set. Get out some marbles. We'll call these marbles "electrons". Find a straight row of dimples in the checker board. We'll call these dimples "holes". Fill all of the dimples in this straight row of "holes" with "electrons" (marbles) except the rightmost hole.

Now move the rightmost marble (electron) one hole to the right. Now move the next marble one hole to the right. Continue doing this until the hole is at the left end of the row. Observe the "electrons" and the "hole" as you move the marbles. Are not the electrons (marbles) moving from left to right? Observe the empty dimple in the row as you are moving the marbles. Does it not appear to move from right to left?

Voila! You now understand hole flow and electron flow.

"No frame of reference is preferred." Einstein

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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 6:26 am 
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^ This is what happens when you get a bunch of engineers talking shop.


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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 9:44 am 
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Find the classic paper, "The Pure Electron Discharge" by Irving Langmuir.


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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 12:27 pm 
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Regardless of what convention used, we have the concept of either holes or electrons "flowing" in a closed circuit.

Here's a thought problem:

If you feed in some electrons at one end, would you expect to get those same electrons at the other end? If you do not get ALL of them, would you expect to get even one?

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 2:55 pm 
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pixellany wrote:
Regardless of what convention used, we have the concept of either holes or electrons "flowing" in a closed circuit.

Here's a thought problem:

If you feed in some electrons at one end, would you expect to get those same electrons at the other end? If you do not get ALL of them, would you expect to get even one?


AC or DC :mrgreen:


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 Post subject: Re: Electron Tube
PostPosted: May Sat 04, 2019 4:41 pm 
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We can only hope it’s DC. the thought of alternating holes is just too much

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