Re: Experiment - Displacement Current's Magnetic Fields

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi,

I guess "I" was the proponent of the Malcolm's ruler theory that proved to
be inaccurate.  I am not sure Malcolm himself was ever convinced ;-)  My
testing at the time eliminated the sine function for a voltage profile.  I
had a rough idea of the profile then and Malcolm suggested the ruler
analogy at the same time.  It generally fit well and the early versions of
E-Tesla used voltage profiles "justified" by the idea.  E-Tesla could not
have worked with sine functions.  Without some "next step" in theory it
never would have worked at all.  So it was a rather short lived idea but it
did provide a step that was needed at the time for E-Tesla to get off the
ground.  The ruler analogy was inaccurate but not in critical places and
the accuracy it gave was fairly good considering.  E-Tesla works fairly
well with it.

I never could mathematically justify the ruler model.  It never worked out
for the reasons Paul mentions.  But it was the best I had at the time.

If there is any "blame" for the model, blame "me"...  Also blame me for
associating Malcolm's name to a model that did not work out.

Of course, later the more accurate and justifiable model was developed and
that is what we go by now.  But at the time, the ruler model was a big
stepping stone.

Cheers,

	Terry


At 12:14 PM 3/13/2002 +0000, you wrote:
>I wrote:
>> Reliance on belief is nearly always fatal for
>> progress - Malcolm's ruler, ...
>
>Malcolm wrote:
>> I hope a crude and early attempt at modelling the resonator
>> through a mechanical analogy is not taken by anyone as a
>> doctrine.
>
>Well I didn't mean to suggest that the flexing ruler analogy was
>cranky or doctrine, but it works well as an illustration of how
>these beliefs become established. The ruler voltage profile would
>not have passed some fairly basic sanity checks, yet it was
>beginning to find itself used as an input assumption in computer
>programs, etc, in a way similar to the use of 1/4 wave wire length
>and DC inductance in Fres calculations, which become established
>simply by going unchallenged.
>
>If you need a voltage profile and you don't have one, you have no
>choice but to guess one.  This often happens in physics and you just
>have to do the best you can to qualify your guess with whatever
>cross checks that you can.
>
>In the case of the ruler analogy, the rising voltage gradient 
>towards the top of the coil is immediately suspicious, since it
>implies not only a lot of current in that part of the coil (which
>is incompatible with a reasonable guess at the capacitance profile),
>but also implies a vastly increasing coil current as you approach
>the top, which defies explanation.  A safer and justifiable guess
>would have been a sine.
>--
>Paul Nicholson
>--
>