RE: RE: weird resonance with HV cap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Your problem is one of methodology.  Here's a couple of rules that must
be observed, or else crazy measurements will result.

1) Primary and secondary resonance measurements must be made such that
the side you're NOT measuring does not influence the side you are.  When
making primary-side measurements, you must completely remove the
secondary coil so there's no coupling between them.  When making
secondary side measurements, the secondary should be mounted on the TC
in the normal way (so that capacitance to the earth is the same as when
operating), but the primary circuit must be open (the spark gap must not
be shorted).

2) For secondary measurements, driving the base is correct, but nothing
but the topload must be attached or even near (less than a couple feet)
the top of the secondary or it will significantly affect the frequency.
Hanging a short wire to a scope probe a few feet away from the top load
will easily pickup the resonance peak.

I don't see any reason to use both scope channels.  Just look at one
thing at a time.  If there's two L-C circuits present, they'll never be
at exactly the same frequency and will give you readings that will make
no sense.

Regards, Gary Lau
MA, USA


> Well, first I just measured the secondary resonance. I drove the
bottom
> of the secondary with one lead of the gen and grounded the other and
> then probed the topload with the scope probe and I had the gen and
> scope and ground wires as far away from the topload as possible to
make
> the capacitance as close to what the actual capacitance between the
> topload and earth really is. Now I'm driving the primary with the gen
> and viewing the primary on ch. 1 and probing the secondary on ch. 2.
If
> both circuits are matched I should see the amplitude of the primary
> rise and then see a big rise in the signal from the topload. I'm going
> to try some saltwater caps with some hdpe buckets I just got. I really
> need to get this thing done so I won't have any excuse for not working
> on my thesis. :)
>