Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Aug Sun 18, 2019 8:18 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 28 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: Electron Tube
PostPosted: May Sun 05, 2019 2:59 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1189
Location: Cedar Rapids, Iowa, USA
For the though problem, I would not expect the same electrons input at one end to appear at the other. I like the Chinese Checkers analogy. It is moot, though, because there is no way to tag a single electron to follow its movement.


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Sun 05, 2019 6:49 am 
Member
User avatar

Joined: Nov Sat 26, 2011 4:09 am
Posts: 9559
Location: Texas. USA
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?
If it's AC then there's no chance at all of getting 'out the other end' what you put in. They just oscillate back and forth (and not the same ones. See below). If it's a DC circuit the odds are only a microscopic amount above zero (if you wait long enough, like the rest of your life).

Even "electron flow" is a bit misleading. It's really the electric FIELD that propagates (at near light speed). The electrons, however, drift at something like a few millimeters per HOUR. Further, they move at random. Assuming a metal conductor, there's not 'one' electron but a cloud around the atom and which one 'moves' is a crap shoot, not to mention, absent an electric field, they 'move' in all directions. The electric field just causes 'some' of them to, on average, move (drift) in the 'proper' direction.

So, the instant your electron enters the conductor it gets captured by an atom. Whether it even moves to another atom is random and then the odds of it moving in the 'right' direction is only a little above zero. Now multiply the 'odds' of it just happening to drift the right way once by of the billions upon billions of atoms along the path and you get a really small number indeed.


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Mon 06, 2019 2:14 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26198
Location: Annapolis, MD
We're mostly in agreement, but I think there is a finite chance of getting the same electron out with either DC or AC. To be sure, with AC, the odds are pretty small.......:)

For more permanent brain damage, how would one ever KNOW if they gotten the same electron??

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


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Mon 06, 2019 5:10 pm 
Member
User avatar

Joined: Nov Sat 26, 2011 4:09 am
Posts: 9559
Location: Texas. USA
pixellany wrote:
We're mostly in agreement, but I think there is a finite chance of getting the same electron out with either DC or AC. To be sure, with AC, the odds are pretty small.......:)

For more permanent brain damage, how would one ever KNOW if they gotten the same electron??
For AC, if it's the same end there's a miniscule chance. I was assuming you meant 'the other' end.

Yes, there's a 'chance' but it's vanishingly small. So small you might as well call it '0'. You'd be closer than any other number.

But, you'd never know. One electron is pretty much indistinguishable from any other electron, as long as they have the same spin. On the other hand, 'your' electron's spin could randomly flip, so it's a distinction without a difference.


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Mon 06, 2019 5:33 pm 
Member

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4592
Location: Sunbury, Ohio 43074
electrons are all the same? Pffffffffff what about their feelings? Their individuality? Their identity??? Electrons are getting pretty tired of hearing "you're all the same"........

oops is that political???? :-D. 8) :roll:

_________________
Preserving the history of electronics, one boat anchor at a time! :)
www.bbtvtestequipment.com


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Mon 06, 2019 7:27 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 32371
Location: SoCal, 91387
Barry H Bennett wrote:
electrons are all the same? Pffffffffff what about their feelings? Their individuality? Their identity??? Electrons are getting pretty tired of hearing "you're all the same"........

oops is that political???? :-D. 8) :roll:

Umm, no, you are just being "politically correct"... :wink:

_________________
\\\\\\\\\\\\\\\\\\\\\\\\He Who Dies With The Most Radios Wins//////////////////


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Thu 16, 2019 12:56 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4866
Location: Gainesville, Florida
solder electrons or copper electrons? and maybe some carbon electrons from a burnt resistor. small amount of electrons equals a small amount of current :|


Top
 Profile  
 
 Post subject: Re: Electron Tube
PostPosted: May Sun 19, 2019 8:49 am 
Member
User avatar

Joined: Oct Sun 18, 2009 5:38 am
Posts: 3682
Location: Tyler, Texas 75707-4212
Ah, Quantum Mechanics and Theoretical Physics.....heady stuff.

Actually, it is said that there is a slow but calculable movement of individual electrons through a conductor from one end to the other, but the drift velocity is very low, IIRC <1mm/hr.

Some references, since we are on the subject.

https://www.physicsforums.com/threads/e ... tor.39876/

https://www.physicsforums.com/threads/h ... or.574282/

And most likely outdated but improved upon:
https://en.wikipedia.org/wiki/Drude_model

When I was in school, I gave serious thought to becoming a Theoretical Physicist. Kind of glad I didn't. I'd probably have gone insane.


I have studied some of this, casually....but I'll bow out due to my overall lack of knowledge of the topic. But I do find it intriguing, especially with new high temps SC's being developed.

_________________
I'm right 97% of the time. Who cares about the other 4%!

-.-. --- .-.. -.. / ---.. ----- --...


Top
 Profile  
 
Post New Topic Post Reply  [ 28 posts ]  Go to page Previous  1, 2

All times are UTC [ DST ]


Who is online

Users browsing this forum: pixellany and 7 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB