# Re: sec input impedance

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

Hi,

Paul Nicholson and his TSSP project could answer such a question.

See:
http://www.abelian.demon.co.uk/tssp/

He has a little mail list going to for this project (heavy thoery :-)).
Instructions are at his site above.

Paul has programs that model the secondary to a very high degree.  Has all
those resonances and such taken into account.  A rough draft of the ideas
are at:

http://www.abelian.demon.co.uk/tssp/pn2511.pdf.zip

Pretty high level math stuff but it is what is need to answer questions
such as yours ;-)

Cheers,

Terry

At 07:53 PM 7/30/2001 +0300, you wrote:
>Hi,
>
>after quite some pause, I finally got around to carry on with my solid
>state TC project.
>
>My question now: how do you calculate the TC secondary input/base
>impedance, for an unloaded seconday coil? Ok measuring some arbitary
>coils might be easy, but I'd like to get the height&diameter&turns
>values so I could make a coil of driver matching impedance, without
>trial and error.
>
>To get the simplest estimate of the input impedance, is it just the AC
>resistance of the coil?
>
>I've some tables with AWG# vs. AC/DC resistance ratios. My thinking is
>that 1) calculate dimensions for wanted f_res with given wire AWG#, 2)
>calculate DC resistance from total wire length, 3) calculate AC
>resistance with help of table. Ok the table is valid only for straigt
>conductors, but any ideas if the calculated value is still "in range"
>(+-10%?) of actual AC resistance? Anyone done this before or know if
>this is totally wrong?
>
>many thanks!
>
> - Jan
>

```