RE: help needed with building a mini table top tesla coil

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

Yes that capacitor does sound small. What size and type of transformer are
you using?
0.00795µF (micro Farads) sounds more like what you should be after.

The type of capacitor that most people use for TC work today is an MMC
(multi mini capacitor), which is an HV capacitor built of lots of lower
voltage caps.

Do a search for MMC in the archives of this list and Google it on the web
too.

examples:
http://teslacoils4christ-dot-org/mark.stolz/capacitor/mmc.htm
http://deepfriedneon-dot-com/tesla_mmc.html
http://www.davekearley.co.uk/Tesla%20Coil/TankCapacitor.html

Calculations:
http://www.tesla-2-dot-org/~mikeh/files/programs/MMCcalc2xls.zip

Hope this helps,

Tom L.

 > Original poster: mizpoon <mizpoon-at-burningart-dot-com>
 >
 > Hi everything,
 >
 > firstly, thanks for your advice on my tesla coil project.
 >
 > i'm now looking for the right capcitor for my tesla coil and
 > am running
 > into difficulties.
 >
 > the capacitor I think I need is about 0.00795 pFarads and is rated at
 > 10KV.
 >
 > However, when calling up a few places, this kind of capacitor
 > is hard to
 > find... do you guys have any idea where I could find such a thing?
 >
 > everyone I talk to says that the capacitor is tiny, and that
 > I'm trying to
 > get the wrong thing... what do you think is the problem here?
 >
 > I know that Ebay has many capacitors for sale, but there are
 > pretty jumbo
 > caps for a larger tesla coil...
 >
 >
 >
 > On Wed, 4 Feb 2004, Tesla list wrote:
 >
 >  > Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
 >  >
 >  > On 4 Feb 2004, at 11:49, Tesla list wrote:
 >  >
 >  >  > Original poster: mizpoon <mizpoon-at-burningart-dot-com>
 >  >  >
 >  >  > Hello everyone,
 >  >  >
 >  >  > I was hoping you could help me with my first table top
 >  >  > tesla coil. This is really my first high voltage
 >  >  > experiment, so any input you have would be very
 >  >  > helpful.
 >  >  >
 >  >  > I have a mini secondary coil and toroid, and am trying
 >  >  > to figure out its resonant frequency so that I can
 >  >  > size up the transformer and capacitor I need for the
 >  >  > primary.
 >  >  >
 >  >  > my secondary coil has a radius of 0.5 inches, 7inches
 >  >  > high, and has 448 turns of very fine wire.
 >  >  >
 >  >  > the toroid is a brass doorknob (!), about 2.125 inches
 >  >  > wide, 1.5 inches tall.
 >  >  >
 >  >  > According to my calculations, I have an inductance of
 >  >  > 673 mhenries, and a capacitance of ~ 7 micro farads
 >  >  > (for both the coil and the toroid), leading to
 >  >
 >  > I do believe the units should be microHenries and
 > picoFarads. On the
 >  > face of it, the values look OK.
 >  >
 >  > Malcolm
 >  >
 >  >  > -- a frequency of 3887883 hertz --
 >  >  >
 >  >  > -- a transformer of 10K at 30ma, and a capacitor at
 > 0.00795 mfarads
 >  >  > --
 >  >  >
 >  >  >
 >  >  > before I go ahead with these calculations, can you
 >  >  > tell me if this seems even vaguely right, or am I way
 >  >  > off with these calculations?
 >  >  >
 >  >  > I used this site for most of my calculations btw:-
 >  >  > http://home.earthlink-dot-net/~electronxlc/formulas.html
 >  >  >
 >  >  > Thanks again for all your help,
 >  >  >
 >  >  > mizpoon
 >  >  >
 >  >  >
 >  >  >
 >  >
 >  >
 >  >
 >
 >