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D & B, last part II


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From:  Keith Nagel [SMTP:knagel-at-cnct-dot-com]
Sent:  Friday, March 06, 1998 8:29 PM
To:  Tesla List
Subject:  Re: D & B, last part II

At 07:52 PM 3/5/98 -0600, you wrote:
>
>----------
>From:  L.Robertson [SMTP:LWRobertson-at-email.msn-dot-com]
>Sent:  Thursday, March 05, 1998 7:32 PM
>To:  Tesla Builders
>Subject:  D & B, last part II
>
>K. Nagel and all ...
>
>The part of the experiment showing rectification
>was done with a normal AC Tesla coil. I used a 
>15 kV / 60 ma neon transformer.In each HV lead
>was a 200 ohm wirewound resistor, which attached 
>directly to each end of a static spark gap. A 0.012
>uF cap and the primary coil complete the circuit.

This I find quite remarkable. I thought from the
earlier post that the driver was DC. What was the polarity
of the elevated terminal side of the cap?

>
>The big Aerovox cap (1.8 uF / 60 kV ) was connected
>between the bottom of the secondary and ground.
>
>You don't need such a big cap. I also used a salt
>water cap made from a half-gallon pickle jar - 0.0015 uF
>and it charged up just like the Aerovox, only faster.
>Anyone who can produce a few inches of spark should
>be able to achieve similar results.

I would think the tuning would be substantially altered
with such a high reactance in series with the coil 
( using the small cap ). 

>
>The rectification business was an unexpected side effect.
>I was really trying to increase spark intensity by driving
>some DC down the ionization channel, which was done
>by charging up the Aerovox with a separate DC supply.
>This DC supply was not connected when I measured the
>rectified current.
>

Yeah, I gathered the discharge must have been quite nice.
You don't mention the secondary resistance and reactance;
I'd imagine a high frequency coil to be ideal for the
enhanced discharge effect. 

>I must say, though, anyone who needs to produce a real
>lightning bolt to ground can pick up these big pulse
>discharge caps for cheap at surplus places; and coupled with
>a modest Tesla coil generate significant discharge current.
>
>LR
>

Again I would imagine that the spark at the secondary
is the source of rectification. I'm puzzled by the issue
of polarity; did you notice a single polarity for all
experiments or did it change with each? Sorry for all
the questions... 


PS:

I'm looking for these for pulse work with NMR, are any of the
surplus houses you mention mail order?