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Re: doorknob capacitor



Tesla List wrote:
> 
> >From ed-at-alumni.caltech.eduSun Sep  1 21:59:48 1996
> Date: Sun, 1 Sep 1996 11:42:18 -0700 (PDT)
> From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
> To: tesla-at-pupman-dot-com
> Subject: Re: doorknob capacitor
> 
>         I think Richard is being a little pessimistic here.  I have
> been running three of what sounds like the same capacitor here for
> about a year (at most a minute at a time, to be honest) and they seem
> to work OK.  They do heat up, which will surely result in breakdown,
> and the capacitance is temperature sensitive enough that the change
> in coil tuning with (even room) temperature is quite appareciable.
>         If that's all I had I'd use it, while plotting to get something
> better.  I have a couple of the C.P. capacitors here which I have yet
> to fire up, but I expect great things out of them.
>         By the way, I should have mentioned I'm using the doorknobs
> with a 12 kV, 60 ma transformer running about 6 amps primary current.
> Getting  good (at least for me) results, 24" plus sparks from a 3" OD
> by 16" high coil resonating around 270 kHz.  By no means optimum, but
> the results are good enough to satisfy visitors and allow for various
> toroid experiments which completely verify the benefits reported by
> the Richmond Richard.
>         My nephew, who teaches high school science down near San Diego,
> also bought about 30 of the 4700 mmfd (most of them are nearer 3200,
> by the way) capacitors from the same source I did, and his students
> have been having a lot of fun making various coils, all powered with
> the same 12 kV, 60 ma transformers of which George found an almost
> unlimited, free (to high schools, at least) source.
>         By the way, having popped a few doorknobs at various times, I
> can verify the loss of silver.  However, for at least two of the capacitors
> which failed, I believe it started with a break in the silver due to
> the fact that the studs were not secure in the plastic potting, and probably
> rotated a bit which broke the original continuity and provide a site
> for arcing.  As soon as that started, of course, the silver was indeed
> "eaten away" by the very large surge currents.
> For what it's worth,
> Ed PhillipsHi,some of the best places in L.A.,Ca. to purchase "doorknobs" are-Apex 
electronics in Sun Valley-(818) 767-7202- They have 30kv to 40kv 3900pf 
for about $2.00ea. C&K in Pasadina,Ca. and Davilyn Corp in North 
Hollywood,I personally prefer High Energy Corp. P.O.Box 308,Lower Valley 
Rd. Parkesburg,Pennsylvania (215) 593-2800, They will custom make you a 
Polypropylene Pulse Cap.(designed for hi repetition rate)has Energol 
II,with extended foils, built into a extruded tube.Get this there PL 
.2uf -at- 40kv has a case size of 5"x 7.88"x 12",not bad if you figure home 
brew caps are quite large,messy,blow up and are around .02uf,mind you 
look at all the fun your missing?,and yes that oil does make a good 
laxative!                                          
Bill  hb-at-earthlink-dot-net