# (Fwd) Re: Vortex gap loss measurements

```Just to clarify (after a memory jog):

On 5 Sep 00, at 9:39, "Tesla list" <tesla-at-pupman.co wrote:

> Hi Antonio,
>
> On 4 Sep 00, at 12:35, Tesla list wrote:
>
> > Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> >
> > Tesla list wrote:

<snip>
> > Note that unless the primary losses are very high, you can
> > approximate exp(-a*t) as 1-a*t with great precision for the
> > time used for complete energy transfer to the secondary (the
> > intial value and the first derivative fot t=0 are identical).
> > The transfer takes just a few cycles, and modeling the gap as a linear
> > resistor during this time, if the main difference is that the decay
> > is linear and not exponential, doesn't make significant difference.
> > ("a" would be Rgap/(2*Lprimary) if you consider only the primary
> > circuit. Considering the secondary, there are two time constants
> > in the system, a compliated function of the element values and
> > losses in the entire circuit.)
> >
> > Antonio Carlos M. de Queiroz
>
> A couple of years ago I mocked up a couple of bench circuits,
> one using a pair of diodes to simulate the gap and another
> using pure resistance tailored so that the ringdown amplitudes
> started identically. Some tailoring of values in the diode
> circuit was needed to obtain a linear ringdown as observed
> using a real gap (I obtained both log and antilog with various
> other values). I found a clear deviation occurring by the
> second peak of ring. While it wasn't much in voltage terms it
> is worth noting that primary energy is proportional to V^2
> rather than V so energy differences were significant. I think
> John Freau's results are at least indicative and point in a
> definite direction.

The "value" I tailored was the initial primary voltage, not
the L and C circuit values. L and C were the same for both
tests. Obviously, the diode characteristics are largely
invariant.

Apologies,
malcolm

> In my most humble opinion.
> Malcolm
>
>

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```