Re: eddy current with secondary coil

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

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
 >
 > Tesla list wrote:
 >  >
 >  > Original poster: Ed Phillips <evp-at-pacbell-dot-net>
 >
 >  >         You fail to mention that, at least to some people, the 
calculations
 >  > themselves provide intellectual satisfaction even when the improved
 >  > results are of no significance.  I suspect you experience that
 >  > satisfaction yourself.
 >
 > Surely. I like to see that the models really work.
 >
 >  >         In my "radio work" I've always found that putting a few extra
 > turns on
 >  > the coil of a fixed-tuned circuit and pulling off turns to get the
 >  > desired exact tuning is the simplest and quickest way to get there.
 >  > Same applies to cored inductors for audio-frequency filter work.
 >
 > Ok for single inductors, but there are cases when they must be precise
 > and it's not practical to make adjustments. Some cases are classical
 > passive filters, and modern RF microelectronics.

	By classical filters do you mean such things as the horrific
"m-derived" design or just passive filters in general?  I've noticed
that guys who do filter design for a living often bridge their
capacitors to be as close as practical and, when really tight tolerances
are required, adjust the associated inductors to some criterion such as
resonant frequency.  For production filters a part of the design may be
a detailed alignment procedure for each circuit branch which could be
isolated.

	The design of "modern RF microelectronics" has certainly promulgated
the use of extremely sophisticated modeling tools which are probably
overkill for normal inductors.


 > Even magnifiers need
 > a precise starting design, because it's difficult to adjust the
 > inductors
 > later.

	I haven't tried to build a magnifier but can see your point.  When you
say "it's difficult to adjust the inductors later" I assume you mean
that it's hard to correlate the tuning and its results?

 > Antonio Carlos M. de Queiroz

	By the way, I love precision (even over accuracy at times) and wasn't
trying to ridicule attempts to achieve it and accuracy as well!

Ed