Re: Surfing the electric wave?

Lets see- at DC the electrons bumble slowly along playing musical chairs
while for AC, they really don't go anywhere- merely wobble back and forth -
No zipping involved.

If this works for you- fine but why complicate things with an incorrect
analogy?
--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------
"Polymath" <(E-Mail Removed)> wrote in message
news:42dea6ca$(E-Mail Removed)...
>I wonder how many of you out there who design
> circuits imagine yourself riding on an electron as it whizzes
> through the circuit as part of your analytic or diagnostic process?
>
> I find this thought process to be particularly useful in software, of
> all things, imagining being in the midst of the data as it is flowing
> about
> me.
>
> This thought process recurred to me in recent days when thinking about
> microwave circuits where the "tuned ccts" may be little more than
> transmission
> line segments. In trying to picture resonances where the resonance effect
> is
> that of a standing wave, I find it helps to be "in there".
>
>
>
>

"Don Kelly" <(E-Mail Removed)> wrote in message
news:nVVDe.9096$s54.1501@pd7tw2no...
they really don't go anywhere- merely wobble back and forth -
> No zipping involved.
>
> Don Kelly @shawcross.ca
> remove the X to answer

Just about sums up garath's thought process ;c)

Steve H

Steve H wrote:
>
>
> Just about sums up garath's thought process ;c)
>
> Steve H
>
>
His WHAT???He needs a brain for those.
--
;-)
73 de Frank Turner-Smith G3VKI - mine's a pint.
http://turner-smith.co.uk

"Polymath" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> What's incorrect about it? Have you considered the speed
> acquired while moving along the mean free path in the Druse
> model?
>
> Indeed, insofar as this thread is posted in a thread for Radio Hams,
> perhaps
> you'd care to explain to them, in terms of the educational attainment that
> they
> must have to qualify, why you consider it to be wrong, and also say what
> analogy
> you think is being alluded to - I did not posit any analogy.
>
> "Don Kelly" <(E-Mail Removed)> wrote in message
> news:nVVDe.9096$s54.1501@pd7tw2no...
>> Lets see- at DC the electrons bumble slowly along playing musical chairs
>> while for AC, they really don't go anywhere- merely wobble back and
>> forth - No zipping involved.
>>
>> If this works for you- fine but why complicate things with an incorrect
>> analogy?
>> --
>>
>> Don Kelly @shawcross.ca
>> remove the X to answer
>> ----------------------------
>> "Polymath" <(E-Mail Removed)> wrote in message
>> news:42dea6ca$(E-Mail Removed)...
>>>I wonder how many of you out there who design
>>> circuits imagine yourself riding on an electron as it whizzes
>>> through the circuit as part of your analytic or diagnostic process?
>>>
>>> I find this thought process to be particularly useful in software, of
>>> all things, imagining being in the midst of the data as it is flowing
>>> about
>>> me.
>>>
>>> This thought process recurred to me in recent days when thinking about
>>> microwave circuits where the "tuned ccts" may be little more than
>>> transmission
>>> line segments. In trying to picture resonances where the resonance
>>> effect is
>>> that of a standing wave, I find it helps to be "in there".
>>>
>>>

Quote:
"I wonder how many of you out there who design
>> circuits imagine yourself riding on an electron as it whizzes
>> through the circuit as part of your analytic or diagnostic process?
>>
>> I find this thought process to be particularly useful in software, of
>> all things, imagining being in the midst of the data as it is flowing
>> about
>> me."

This smells of analogy "riding on an electron as it whizzes...".

As for mean free path in a conductor- pretty short. Electron velocity is
low -order of a few meters/sec. A form of musical chairs. This has nothing
to do with the wave velocity.
Do you have evidence otherwise?


--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------

Brian Reay wrote:

>I'm not sure I'd
>suggest anyone "pretends to be an electron", other than as an initial model
>for a total beginner.

ROFL

from
Aero Spike

On Sat, 23 Jul 2005 10:17:31 +0100, Polymath wrote:

> So, the electron whizzes along at a few metres per second.

Don't think so, but I havent' done this in a long time. ;-)

Current = (electrons/m^3) * (area in m^2) * (velocity in m/s) * (electron
charge)

That gives us I(Amps) = n*m^-3 * A*m^2 v*ms-1 Q*C (the units work out
A=C/s) so I=nAvQ solving for v:

v=I/nAQ

Let's pick some numbers:

Let's assume a wire with a cross section of 1mm^2 with a current of 5A.
I= 5
A= 1E-6
n= ~8.5E28 (copper)
Q= 1.6E-19

v= 5/(8.5E28 * 1E-6 * 1.6E-19)
v= .37E-3 or less than a half a millimeter per second.

That's "wizzin", alright. ;-)


> How many would you like? 10, say?

A "little" high. ;-)

> OK 31 feet /sec. Now, I remember from my "A" Level maths that 60MPH is
> 88 feet per second, so 31 ft/second (assuming you accept the figure) is
> fair "whizzing along", certainly with respect to any speed that you are
> I might obtain on a bicycle!

I think I could beat a half millimeter per second. ;-)

--
Keith

On Sat, 23 Jul 2005 17:27:26 +0100, Polymath wrote:

> A well-reasoned response, but yours is based on the
> "fluid flow" analysis which assumes that charge is smoothly
> flowing through a pipe. Admittedly, this is the model used
> when developing Maxwell's Equations, as it relies upon there
> being a "Current Density Vector", "J" with flows represented
> as you do below.

Sure, average electron velocity.

> Now, the difficulty with learning electricity is that there are many
> models to go by, each of which is wrong in some respect when
> you learn a little more. Now, in the Drude model (which I erroneously
> remembered as the Druse model), the electrons are treated as little balls
> which leap forward under the influence of the applied electric field
> and then collide with atoms and come to a halt, before leaping onwards
> again. In order to match the average speeds that you analyse below,
> the Drude model results in a much higher instantaneous speed between
> the collisions.

It would seem that the energy needed to accelerate the electrons (non-zero
mass), which would then be dissipated when the collision occured. What
is the source/sink of this energy? What is the carrier? Nah, Occam seems
to apply here.

> Whatever the speed you wish to believe, if you take the distance
> traversed in relation to the size of your electron, you find that they
> are, indeed, whizzing along.

You're changing your definitions here. Your definition of "wizzing
along" in the article I quoted was 10M/s and compared it to a bicycle.

"certainly with respect to any speed that you are I might obtain on a
bicycle!"

Of course, the parenthetical before that "(assuming you accept the
figure)" is wrong. I don't accept the figure and showed (poly)math.


> However, electrons are not little balls, but wave packets, so the Drude
> model favoured by the 13-year-old pedants such as Mrs.Nugatory and Brian
> Reay has its faults. Do I sneer at them in an infantile manner and
> suggest that theirs' are the attitudes of "total beginners" because they
> have chosen a model which is wrong? No. Mrs.Nugatory is as Mrs.Nugatory
> does.

Please!

> Now, the actual model you use at any one time must be one that suits you
> and gets you the right answer in any engineering problem, so, setting
> aside the pedantic-and-sometimes-wrong-straw-men that are flying around,
> returning to the original question - do you ever imagine yourself inside
> your circuitry as an assistance to analysis and diagnosis?

No. I try not to make electronics personal. ;-)

> "keith" <(E-Mail Removed)> wrote in message
> news(E-Mail Removed)...
>> On Sat, 23 Jul 2005 10:17:31 +0100, Polymath wrote:
>>
>>> So, the electron whizzes along at a few metres per second.
>>
>> Don't think so, but I havent' done this in a long time. ;-)
>>
>> Current = (electrons/m^3) * (area in m^2) * (velocity in m/s) *
>> (electron charge)
>>
>> That gives us I(Amps) = n*m^-3 * A*m^2 v*ms-1 Q*C (the units work out
>> A=C/s) so I=nAvQ solving for v:
>>
>> v=I/nAQ
>>
>> Let's pick some numbers:
>>
>> Let's assume a wire with a cross section of 1mm^2 with a current of 5A.
>> I= 5
>> A= 1E-6
>> n= ~8.5E28 (copper)
>> Q= 1.6E-19
>>
>> v= 5/(8.5E28 * 1E-6 * 1.6E-19)
>> v= .37E-3 or less than a half a millimeter per second.
>>
>> That's "wizzin", alright. ;-)
>>
>>
>>> How many would you like? 10, say?
>>
>> A "little" high. ;-)
>>
>>> OK 31 feet /sec. Now, I remember from my "A" Level maths that 60MPH is
>>> 88 feet per second, so 31 ft/second (assuming you accept the figure)
>>> is fair "whizzing along", certainly with respect to any speed that you
>>> are I might obtain on a bicycle!
>>
>> I think I could beat a half millimeter per second. ;-)
>>
--
Keith

P.S. Your newsreader is broken, but what's new (Outhouse Excess).

keith wrote:

>On Sat, 23 Jul 2005 17:27:26 +0100, Polymath wrote:
>
>> Whatever the speed you wish to believe, if you take the distance
>> traversed in relation to the size of your electron, you find that they
>> are, indeed, whizzing along.
>
>You're changing your definitions here. Your definition of "wizzing
>along" in the article I quoted was 10M/s and compared it to a bicycle.
>

This is common from the OP.

He posts some claptrap statement, and when challenged on it, gradually
introduces more and more caveats and qualifications regarding his
origninal posting.

It's a tiresome, ineffective, and juvenile tactic.

from
Aero Spike

On Sat, 23 Jul 2005 18:27:04 +0100, "Polymath"
<(E-Mail Removed)> wrote:

>Not at all. I starting chatting about analytic approaches. It was
>others, mainly Mrs.Nugatory and Brian Reay, who put up Straw
>Men by reading things that I did not say. Unfortunately, this is a habit
>of theirs, and particularly so from Mrs.Nugatory. I'll post a one-liner,
>and she'll respond with 50 pages (read up on her responses to my
>informing the NG that cheap dehumidifiers were available from a
>local store!) as the result of reading between-the-lines things that I
>did not post. The misunderstandings are hers, but when I clarify
>matters she'll then accuse me of weasling when the only misunderstandings
>have been hers. She seems to expect throw-away lines given in
>clubman's chit-chat to have the rigour of a PhD thesis; but then,
>that's the pedantic mind of a 13-year-old for you!

It does seem appropriate to comment on the fact that the school summer
holidays are upon us. As you are aware Mrs Nugatory dreads them
because her cowardice, in the face of children, will once again
confine him to cwoering behind his twitching curtains. With little
else to do but bore himself silly watching his copy of 'The Bridges at
Toko-Ri' he will also resort to his usual tactic of posting crap to
this NG and whizzing to Google to get information that he will pass
off as his own. You have been warned!

I append a few short articles of his to illustrate his shortcomings:-

> On Sat, 28 Feb 2004 14:04:36 +0000, RVMJ 99g <(E-Mail Removed)> wrote:
>
> >Having been assaulted by two 'young people' in the garage at the back
> >of my house, during which (being aware of the issues) I neither
> >reacted or retaliated, I count myself lucky that they didn't concoct a
> >story about the reverse being true. There were were no independent
> >witnesses, and so their uncorroborated word as 'young people' would
> >have been accepted without question, as is the normal practice.
> >As they never surfaced before 10:30 on weekend mornings, I made sure
> >that any outside work I wanted to do, such as car servicing or
> >gardening, was done before that time, at which point I made myself
> >scarce. Taking leave and doing jobs during the week wasn't on, as one
> >couldn't guarantee that they wouldn't bunk off from school.
> >As they used to congregate in the area of the garages, it meant I
> >could never use my motorcycle without risking being accosted by them
> >on my return, as there was no way of seeing if they were present. So
> >for a year or two, until they discovered the world outside the area
> >contained people of the opposite gender, I was a prisoner in my own
> >house. Again, I count myself lucky that they only scratched my car
> >four times, broke five radio aerials and two door mirrors, rendered
> >the door-locks inoperative with matchsticks and slashed the tyres
> >once. Young people need protection, did you say?


>The reason is obscure, but he suffered a contemporeanous 'ISP
>failure'


>I've checked for tuning capacitor plates not rubbing each other, and
>correct earthing for the tuning capacitor main shaft wipers. I can't
>think of anything else.
>Many thanks to all of you who posted and e-mailed replies.
>The cause of the crackly noise (on rechecking everything) was found to
>be a double-fault on the mixer capacitor rotor-plate earthing
>contacts.


>But if you thought he was a nit-picker, you
>haven't met me yet.


>"ignoramuses"?
>What kind of, er, hybrid is that?
>Or did it 'develop'?

On Sat, 23 Jul 2005 07:38:54 GMT, "Brian Reay" <(E-Mail Removed)>
wrote:

>"Don Kelly" <(E-Mail Removed)> wrote in message
>news:WekEe.20321$%K2.12161@pd7tw1no...
> > > "Don Kelly" <(E-Mail Removed)> wrote in message
> >
>> This smells of analogy "riding on an electron as it whizzes...".
>>
>> As for mean free path in a conductor- pretty short. Electron velocity is
>> low -order of a few meters/sec. A form of musical chairs. This has
>nothing
>> to do with the wave velocity.
>
>Indeed Don, I've also heard the 'drunken man' analogy - the electrons bumble
>along bumping into the material's atomic lattice.
>
>The mean free path in something like copper is 10's of nm. If memory serves,
>the theory of the conduction mechanism is attributed to Drude (his "Free
>Electron Theory") and, at a top level, explains the mechanism of how
>conductivity varies with temperature (as the material cools the probability
>of collisions with the atomic lattice structure decreases, so the mean free
>path of the electrons increases). I say "top level" as Drude's work assumed
>a perfect atomic lattice- another chap (Matthews? or Matherson? something
>like that) refined the work to allow for impurities.
>
>Also, as I recall, it is Drude's work that led to electron microscopy- if
>the electrons could "whizz" through atomic structure you'd not see much,
>analogous to 'over exposure'?
>
No. It was de Broglie's idea of wave/particle duality and its
consequence that electrons had an effective wavelength far shorter
than visible light that led to the development of microscopes with
much higher resolving power. Abbe had already shown the relationship
between wavelength and resolving power in optical microscopes.