Re: Just getting started

To: tesla-at-pupman-dot-com
Subject: Re: Just getting started
From: Rodney Davies <rodney-at-johnxt7.anu.edu.au>
Date: Thu, 13 Jun 1996 00:41:45 +1000 (EST)
Hi Aaron,

On Tue, 11 Jun 1996, Tesla List wrote:

>   should the capacitor rating match the transformer output, or the Tesla coil
> output (whatever that is)?  Can I build a coil with a 15,000 V neon
> transformer and three 6000 V capacitors connected in series?

Well, 3 in series will give you 18,000 V (assume peak) rating.
The perhaps best approach to take is cap voltage ratings of at least 
twice the transformer voltage - for the sake of keeping your caps alive!

Also, just check to make sure your cap uF (microfarad) values match your 
neons.

I use the formula -
		1
	C = ---------
	    2*Pi*F*R

Where Pi = 3.1415........
      F = Frequency = 60Hz (I think that's your mains frequency...ours is 
50Hz)
      R = impedence of the neon transformer (which is Volts/Current (V/I))
      C is in Farads.


eg calculation - 

Assume 15,000V at 30mA (0.03Amps) (substitute current value as necessary)

R = V/I = 15,000/0.03 = 500,000 Ohms

	1
C = ---------------
    2*Pi*60*500,000

  = 0.000000005 Farads 
  = 0.005 micro Farads (I think I converted it correctly??)

I always go by this formula and it hasn't failed me yet...

Anything too high (by a factor of 10 or 100) and your spark gap won't 
work.

This is speaking from experiences I've had....
When I very first started out coiling (about 4 years ago), I had a 
10,000V 30mA Neon and 4 0.5uF 7,500V caps.
Since the neon was centre tapped, I had to have 2 0.5uF caps in series 
on either side of the neon. This made 0.25uF rating at 15,000V.

At the time I didn't know the behaviour of the circuit (I didn't even 
know that it's a magnetic field which makes to voltage in the 
secondary!) and that cap values that were too high, simply didn't work 
with the transformer I was using. 

Hope this helps you a little.... :-)

Happy constructions!

Rod

 -- "Who are the Federal Communications Commission and why do they 
    want my Tesla Coil?"

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| Rodney Davies                                                             |
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