# Re: New Fo, Cself, Ctotal Program

• To: tesla-at-pupman-dot-com
• Subject: Re: New Fo, Cself, Ctotal Program
• From: Terry Fritz <twf-at-verinet-dot-com>
• Date: Mon, 04 Jan 1999 20:37:03 -0700
• Approved: twf-at-verinet-dot-com

```Hi Scott,

At 04:58 PM 1/4/99 -0600, you wrote:
snip.........

>
>What formula is typicaly used to calculate resonant frequency?
>
>        F=1/2 PI L C ?    or    F={[(1/LC)-(R/2L)^2]^.5}/2 PI ?
>
>The former is the typical approximation while the latter requires knowledge
>of load resistance. It's significant with Low-Q's, such as a Tesla secondary
>which I've heard can be as low as 10 when arcing.

Everyone I know of uses the first equation.  The second equation is really
technically correct if you models the system as a simple LCR circuit.  The
reason the second equation is not used is because the term (R/2L)^ is
insignificant compared to the 1/LC term.  In my coil the folling applies:

L = 0.0754
C = 26.93 PF
Req = 270 Ohms

The first equation gives 111.6906395 kHz

The second equation gives 111.690242882 kHz

Not enough difference to worry about in most cases.

If the streamer arcs to ground,  The Fo frequency no longer has any meaning.

>
>capacitance, tending to decrease the frequency. But all this talk of
>frequency can be misleading, as the action happens in the time domain.

That's what computer models are for :-))

Terry

>
>Maybe when arc generation dynamics are understood (by me, anyways), and
>resonant energy transfer is understood (I believe it is), and if a
>technology for dynamic control is applied (I won't open that large can of
>worms), it may be found that by dynamic (time changing) control, large arcs
>can be generated with out a large capacitive top load, which is a fine
>energy store for a growing arc, BUT a significant limiter of possible peak
>(voltage) potential of the secondary.
>
>I feel the urge to write comming on...
>
>

```