# Re: From primary to top terminal

```Hi Finn,

> Original Poster: "Finn Hammer" <f-hammer-at-post5.tele.dk>
>
> Hi guys!
>
> This post contains my background thinking, and ends with a question, and
> an excuse!
>
> Now that my brother has got an interest in making the etesla5x run
> faster, we talk about how a TC actually works. I`m not at much help,
> since my understanding is flaky, but he keeps saying things like: of
> course the secondary is a transmissionline, and: of course there is
> going to be some turns ratio relationships btwn. primary and secondary
> voltages. He used to work with radar and the like in his youth.
>
> My argument against the turns ratio relationship has been that of energy
> conservation: the secondary cannot build up a greater voltage than that
> allowed by the available energy, and the capacity of the top terminal.
> (minus some part that gets stuck, charging the self-c, med-c or
> intrinsic-c or whatever(over my head)).
>
> On the way to the gastank, for cigarettes, this thought struck me: If I
> was going to charge a cap to some voltage, with an ordinary transformer,
> I would probably not want to use a 20 kV transformer to reach a voltage
> of, say, 4 kV would I?. It seems as It would be more appropriate to use
> a 4 kV transformer for that job.
>
> So the question that I arrived at is this:
>
> Will a Teslacoil benefit from being built so that the voltage attainable
> by the rule of turns ratio btwn. primary and secondary matches the
> voltage that can be attained by the rule of conservation of energy?

If you plug your typical inductances into Wheeler's formula and
further assume that the secondary operates as a lumped circuit,
you'll quickly find that for typical primary and secondary h/d's, the
turns ratio is actually the best you can do for a fixed lump of energy.
SQRT(Ls/Lp) doesn't do as well. You can see that if Hs = Hp and Ds
= Dp (i.e. k=1), that ratio reduces to the clssic transformer turns
ratio.  On the other hand it is claimed by proponents of wave action
on a slow wave structure that you can do far better than Ns/Np. I
haven't yet seen much evidence to convince me of that in a non-CW
regime but maybe you can although I think COE still applies to a
lump of capacitance fitted to the top of a resonator which is
appreciably less than a wavelength long at Fr.

Regards,
Malcolm

```