Re: Questions.

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <cwillis-at-guilford.edu>


Hi Josh,

I am familiar with the capacitor you suggested.  It is available at both
Hosfelt and All Electronics for $1.  As far as its RF performance, it seems to
do all right.  It gets much less hot than other similarly sized doorknobs and
ceramics in circuits I have used it in (for tank-capacitance purposes). 
However, capacitance decreases quite a bit when it does warm up.  I think you
could make an MMC with the same ratings that would outperform it and still not
be difficult on the budget.  These little yellow axial caps are useful for RF
bypassing, such as grid leaks on tube coils, and oil capacitors in power
supplies.  My circuit using this capacitor (as a tank capacitor) is described
at:

www.angelfire-dot-com/electronic/cwillis/811acoil.html

This is a tube-type coil.

About your ground: at least you really ought to pound a couple 6' grounding
posts in the moist dirt outside.  Making an excellent RF ground can be a little
time consuming, and it really depends on how big your coil is and where you
want to use it as to just how important this is.  For real small coils, you can
use the wall-socket ground.  You can also try COLD WATER pipes in your
location, if convenient.  Poorly grounded Tesla coils aren't the best
performers and can cause interference problems and RF hot spots in your home
wiring- so if you have nice stuff (like a computer) grounded via the outlet,
try to avoid the cheap and dirty third-prong approach.

-Carl   

-at-
Sent by: "Tesla list" <tesla-at-pupman-dot-com>
02/20/2001 08:22 PM MST

To: tesla-at-pupman-dot-com
cc: 
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Subject: Questions.


Original poster: "Joshua H Ball by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<jhmball-at-juno-dot-com>

Hello list.
I've been on the list for a while and am looking to build a my first coil
in the near future. I have a few questions:

1.  What should be a good target frequency for a coil?  What are the
pro's and con's of a higher or lower frequency?  What effect does the
input ac's frequency have?

2.  I have found some caps I can get for a relatively good price and
would like to use them for my coil.  Are these in the right ballpark for
tesla coils?
.001 UF 10 KV AXIAL CERAMIC DISC CAPACITOR   $ 1.00 each

3.  When demonstrating a coil indoors what do you use for a ground?  Do
you simply run a wire to outside?

4.  Wouldn't a conical secondary be more efficient than a cylindrical
one?  One reason being that the magnetic force from the lower wider part
of the secondary coil would create a higher voltage on the smaller higher
part.  Know what i'm saying?

I think that's all for now.  Thanks,

-Josh B.