Re: tesla coil

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

Original poster: "Gregory Hunter by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>

Hi Mike,

 > I am building my first tesla coil and am pretty
 > limited in my understanding
 > of electronics. I bought plans off the web that were
 > posted on e-bay and
 > have some questions I think you can answer.
 > Between the transformer and the spark gap is a
 > component called a choke
 > constructed of a ferrite torid core -what does it do
 > ?

The purpose of the choke is to allow 60Hz current from
the power supply to reach the tank circuit, while
preventing radio frequency current generated by the
tank circuit from reaching the power supply. I'm
skeptical of it's usefulness. To properly protect the
power supply, you need an RC (resistor-capacitor)
lo-pass filter.

 >
 > The plans call for a pvc pipe with aluminum sheets
 > rolled between plactic
 > sheets with a value of .005 uF  40,000 volts pr cap.
 > Is there any other
 > caps  I can substitute for this labor intensive
 > project ?.If so are they

If you want to roll your own caps on the cheap, a
sixpack of 12oz beer bottle caps will also yield
.005uF. Any number of sixpacks can be wired in
parallel for more capacitance. Beer bottle caps are
very durable. I haven't punctured one in years.

If you don't mind spending some coin for a better
capacitor, an MMC (multi-mini cap) built from
commercially manufactured polypropylene/foil snubber
caps in a series/parallel grid will yield the desired
voltage and capacitance rating in a very neat, compact
package.

 > durable ? I would need a good description to
 > purchase them.
 > I heard that ac caps do not hold a charge once the
 > electricity is turned
 > off. Any comments ?.

Of course they can hold a charge. However, in tesla
coil service said charge is usually bled off by the
power supply as soon as the power is turned off.
Likewise, many coilers place high value bleeder
resistors in series with their tank cap (and across
each individual cap in an MMC array) to safely drain
off any charge after the power is removed.

 > I have to make two. Are they wired in series or
 > parallel.?
 >
 > What relevant information do you need from my tesla
 > coil blueprints so I
 > can construct a  torid ?

Blueprints? We don't need no stinking blueprints! You
can make a fast & cheap toroid using 4" aluminum flex
duct wrapped around two cheap, 9" steel pie pans from
WalMart. The pie pans are glued together back to back
to form a wheel rim. The semi-rigid flex duct (from
ACE, Lowe's, Home Depot, etc.) is then bent around the
pie plates until the ends meet. The joint is covered
with a band of aluminum tape. The flex-duct is then
bonded to the pie plates with a bead of silicone caulk
on both sides. This makes a lightweight, cheap, and
very functional toroid for hobby coiling.

 > Thanks  Mike Biggs
 >

I've actually messed around with most of the things I
suggested here. Drop by my site sometime and have a
look at toroids, capacitors, and assorted lo-budget
coiling stuff. Most of the text is non-technical and
shouldn't be too hard to figure out, even without a
background in electronics or electricity.

Best Regards,


=====
Gregory R. Hunter

http://hot-streamer-dot-com/greg

_