Re: DC secondary components

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

> Yup, wonder what DC rating it would require?
How much current?>> If it were 1 uA, that 0.1uF would charge to 10 V in a
second.

>
> > this would make an excellent science fair project
>
> Indeed.  Glad to see that just building a TC is not enough to qualify
> for a science fair, otherwise it would be just an 'engineering fair'.

Well.... they are typically "Science and Engineering" fairs these (last 30
years, at least) days (GSDSEF, ISEF, etc.), in recognition of the somewhat
blurry line between applied science and theoretical engineering, and
besides, how would you classify mathematical theory researching.

We who are physical science oriented (you must be if you're building a tesla
coil, after all...) can look askance at the "softer" sciences: sociology,
psychology, economics, etc....but there are a lot of folks interested in
such stuff..

In any case, the science fair plea was more for originality...They don't
want to see yet another bare TC, or yet another plants and colors, unless
you've got something novel, and really good experimental technique
(especially with the latter).



>
> [DC pedestal under the coil base]
> Bert wrote:
> > Greg Leyh actually did this experiment a couple of years ago using
> > one of his large coils. He used a high energy capacitor bank
> > charged to a high potential to elevate the base of his secondary.
> Antonio wrote:
> > If I remember correctly, the capacitor was charged by the DC
> > current that appears in the secondary coil as consequence of
> > the rectifying action of streamers.
>
> Oh, so we're not clear which of two different experiments were going
> on here.  Have to do some digging for the original stuff...

It might be both... Hook a cap up and it might charge right up, putting that
DC offset voltage on the coil, until it reaches some sort of equilibrium.

>
> Bert wrote:
> > I suspect that you'd need to elevate the secondary DC potential to
> > a significantly higher potential  (many 10's of kilovolts positive)
> > before you'd actually begin to see changes in streamer behavior.
>
> Thinking about it, I'm inclined to agree.

I'd say you'd need on the order of 25% of the AC voltage to start seeing any
change... One of the folks with the mini coils would be ideally suited for
this experiment...


>
> It might be that inserting a blocking capacitor into the base would
> be a good method of measuring the *average* DC component of the
> streamers, since it integrates it.  Seems to me that the charge
> fetching up on this blocking capacitor would equal the total of
> the +/- charge 'imbalance' achieved within the streamers.

And, you could put a string of NE-2's or some VR tubes across the capacitor
to form a constant voltage ............
>
> >
>