Re: Newbie cap and topload questions

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Mddeming@xxxxxxx 

Hi jvillecheesehead@xxxxxxxxxxxxxxxx


(you need a shorter handle/nickname/ID)

    To try to answer your questions :

In a message dated 1/7/06 9:56:22 P.M. Eastern Standard Time, 
tesla@xxxxxxxxxx writes:
Original poster: jvillecheesehead@xxxxxxxxxxxxxxxx

Hi,
I'm a first time coiler and it took until now for me to finally discover how
useful this list was.  Anyhow, I am using a 15kv 20mA nst and have wound my
secondary of 4" diameter 20" height with 800 turns of 23 gauge wire.  My
question is about a couple options with caps.  First, I am assuming
this 35,000V
.005uf cap from Electronics Goldmine for $2.75 is not suitable for tesla coils
as the site claims and wanted to confirm this.  Here is a link:
http://www.goldmine-elec-products.com/prodinfo.asp?number=G15589&variation=&aitem=72&mitem=91

Answer: Insufficient data to compute. With no manufacturer name or 
model number, no data sheet, there is no way to evaluate the 
usefulness of this cap
 RF response= unknown
ESR             = unknown
Pulse rating  = unknown
Peak current = unknown
Is the 35kV and AC or DC rating?

  My other plan was to use this Phillips 1600V .047uf cap that runs
for a buck a
piece at the same site:
http://www.goldmine-elec-products.com/prodinfo.asp?number=G14832&variation=&aitem=67&mitem=91

Answer: Insufficient data to compute. With only manufacturer's name 
but no model number, no data sheet, there is no way to evaluate the 
usefulness of this cap
 RF response= unknown
ESR             = unknown
Pulse rating  = unknown
Peak current = unknown
Is the 1600V and AC or DC rating?

  According to an excel calculator, I believe using Terry Fritz's
data, the best
reliability/price point would be 2 strings of 19 of these caps.  Upon reading
some other posts it sounds like some people push them harder without any issues
and was wondering if anyone had an opinion on this.

Most people build their second MMC a lot more conservatively than their first.


I also had another quick question about the topload.  For some reason in my
planning (which was a few months ago, couldn't work on the coil while I was at
college) I decided to use a toroid with 3" diameter Al ducting with a total
diameter of about 10 inches.  Using Barton Anderson's JavaTC calculator this in
combination with my other components results in a 390kHz resonant frequency.
The size and frequency differs from many of the coils I have seen
online and was
wondering if there is any problem with using it.

A 3" X 10" is rather small for a 4" TC. The larger the radius of 
curvature, the larger the charge and the higher potential that can be 
reached prior to breakout. A general rule of thumb (NOT a 
commandment) is for toroid minor diameter = secondary tube diameter, 
and major diameter = secondary length.

Lastly, I thought I would share a picture of my spark gap that
includes a simple
modification to the Richard Quick design that allows for increased
adjustability.  Thanks for the help!

Looks good!



Matt D.