Re: More Coupling...

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ludev-at-videotron.ca>

Hi Antonio

Could it be an idea to use an helical secondary for a magnifier coil ( easy
coupling adjustment ).

Luc Benard

Tesla list wrote:

> Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
>
> Tesla list wrote:
>
> > Original poster: "BunnyKiller" <bigfoo39-at-telocity-dot-com>
>
> > while reading all of the coupling threads, I began to wonder about the
> > coupling of
> > a helical primary and if anyone has done any experimenting on the
> distance from
> > the secondary. ( e.g. instead of having a helical primary say 2" from the
> > secondary , how about having it 6 or 8" from the secondary?)
> >
> > would this extra distance decrease the coupling or would it matter?
>
> Certainly the distance affects the coupling. Actually, the coupling
> coefficient for an helical primary is approximately the ratio of
> the areas occupied by the secondary and primary coils, or the square
> of the ratio of their diameters.
> An helical coil uses less wire than any other usual form for the same
> inductance.
>
> Antonio Carlos M. de Queiroz