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Re: DC TC



Hi Bert,
Well I did some searching and found one of the diodes. When I get a chance I
will get out my divider and measure the forward drop on this thing. Maybe it
is some incredibly high value. The number on the device reads:
45XV495
This device is 4 inches long.
When I first started out in coiling I used to use DC all the time. I did
this because all I had were little wimpy transformers at that time. I knew
that I had to give the tank cap time to fully charge. I had a real small 2 x
9" coil that I ran off a 5800V/5mA transformer that I salvaged from an old
copier. When I tried to use it by itself I only got a half inch out of the
coil. When I rectified the output with three HV rectifiers in series (A
completely different type than the one mentioned above-VARO H2523-1) my
output increased to 2". This of course was half wave, but I still got an
improvement over AC, and boy was I exited over that little 2" spark. I had
no idea that in the future I would be making 33" ones! My ultimate goal back
then was one foot. I had one scheme where I was using a small10 kv supply
that put out several micro amps to power a 4.5 x 14" coil. The sparkgap
fired at maybe two breaks per second and I would get 7 inch sparks out of
the secondary. Believe it or not this is the very same secondary that is
producing 33" streamers today. All I did was to add baffles, and an extra
coat of polyurathane. All I needed to do besides that was to change the
sparkgap, the primary, the capacitor, and all the connecting wires. Having
an extra 800 watts certainly helps too!!!

S.G.

> I suspect that adding the diodes prevented some of the energy that was
> left in the tank capacitor from flowing "back" into the transformer's
> leakage inductance during every AC voltage zero-crossing. The
> bidirectional energy transfer that normally occurs between the tank cap
> and the leakage inductance of an NST (even for non-resonant charging
> systems) was prevented by presence of the diodes. This would have the
> impact of reducing the overall efficiency of energy transfer between the
> NST and the tank cap, reducing performance.
>
> Safe coilin' to you!
>
> -- Bert --
>
>
>