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Spark Length was Re: Voltage determination
Hi Malcom, John C., David,
<a few bandwidth snips>
Tesla list wrote:
> Original poster: "Malcolm Watts" <M.J.Watts-at-massey.ac.nz>
> In order to increase Ls you *have* to change something else if
> tune is to be maintained, whether it is decreasing Cs
> (physically smaller coil, hence smaller wire, hence higher
> secondary losses), increasing Cp (in which case you'd have to
> lower Vp in order to retain an identical Ep = same Vout) or
> increasing Lp (in which case the impedance ratio is the same =
> same Vout). I think it is unrealistic to simply attribute
> increased sparklength to a change in one variable only when in
> reality others change or must be changed as well. The
> foregoing arguments assume negligible losses in the primary
> which isn't true either and then of course any modification to
> either coil affects k. Not so simple I would say.
Now this I agree with. It's not as simple as changing Ls, but the equation
posted would suggest otherwise (Spark length = W*Vp*Ls*B).
John, are you saying Ls alone will increase spark length? I'm guessing your not
meaning to and maybe "only" in a case where Ls was originally not optimal for
the coil to begin with. But even then, there must be a point where further
increase of Ls moves away from optimal (regardless of everything else that
changes), which suggest that Ls in the equation can't be used in the
mathematical way expressed.
BTW, optimal Ls (IMHO) is governed by the primary tank design. In other words,
I might be so brave as to suggest that part of the reason H/D becomes a factor
is biased towards a high loss or low loss primary tank circuit.