Tesla Capacitors


There are quite a few people subsrcibed to this list now.  Some have coils up
and running, some are building and some are still thinking about it.  Most of
us can wind the secondary, build the primary, spark gaps, discharge
terminals, etc. but run into a problem with the capacitor.  It is the one
difficult thing to make at home.  I did make two rolled capacitors using
aluminum flashing and .0625 polyethylene.  I did a good careful job building
them.  They both came out at .019 microfarads.  They worked fine for a while
until I finally got up to 12kv and tried to run them for several minutes at a
time and they both eventually failed - punctured the dielectric.

I am convinced that capacitors built like this (with .062 poly) will only
withstand about 9.0kv for any period of time.  If you use .062 you need to
use two of these in series for 12 or 15 kv operation.  My problem was that I
needed .019 mfds.  So I used one capacitor at a time and eventually ruined
them both.  What I really needed to do was to build 4 of these and use them
in series/parallel.  Another option would be to use .093 poly but the
finished value will drop down quite a bit.

I calculated my cost to build these capacitors at about $90.00 each.  This is
about the time Richard Quick suggested buying a commercial made capacitor.  I
got quotes from four different companies.  Condenser Products Corp. in
Brooksville, Florida (phone 904-796-3561) provided the best quote and seemed
to be the most knowledgeable.  They built a custom capacitor for me for
$185.00 including shipping.  This is cheaper than I could have built it for,
it is much smaller than 4 large upright home made capacitors and I'm sure it
will take more abuse.  The value is .025 mfd, 15,000v RMS AC rated for pulse
discharge - Tesla tank circuit operation.  It was tested to 33,000 volts.  I
am currently running at 14,400 volts and about 300ma.  They said it is
designed to handle more current although I did not get a specification on
this.  I hope to get the primary current up to 400 or 500 ma someday.  They
told me today the price for this capacitor would be $220.00 for one and
$198.00 each for 2 - 4.  Five or more $183.00 each.

I just thought I would let everyone know about this.  It may seem like a lot
of money, but I think it is cheaper in the long run and they do build a great

Ed Sonderman