# Re: John's formula, spark length

```Original poster: "colin.heath4 by way of Terry Fritz <twftesla-at-qwest-dot-net>" <colin.heath4-at-ntlworld-dot-com>

surely the other factor is how much of the power goes into the coil
as the cap acts as a reactive ballast the whole circuit can pull so much
power the rest gets sucked up with gap losses especially with a static gap
i could be way off with this though as im only quite new to all this
cheers
colin heath
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, September 03, 2002 7:13 PM
Subject: Re: John's formula, spark length

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Esondrmn-at-aol-dot-com>
>
> In a message dated 8/29/02 12:51:05 PM Pacific Daylight Time,
tesla-at-pupman-dot-com
> writes:
>
>
> >
> > Hi,
> >
> >
> > http://hometown.aol-dot-com/futuret/page5.html
> >
> > It is:
> >
> > Ques: How long will my sparks be for a given input power?
> >
> > Ans: In a well designed TC, the spark length will follow the formula:
> >
> > spark length (inches) = 1.7*sqrt input power (wallplug watts)
> >
> > Cheers,
> >
> >         Terry
>
>
>
>
> Haven't looked at John's page for a while.  Does the formula somehow take
into
> consideration the size of the coil?  My 6.0" diameter coil which I run at
> 6kva should produce about 132" sparks according to the formula.  The best
I
> have achieved is 104".  I do believe that a 10" or 12" diameter coil with
this
> much power input could certainly produce 132" sparks.  For a given size
coil,
> there is a maximum level of power that can be input to the system.  By
just
> using the formula, one could expect 132" sparks with 6,000 watts input to
a
> 3.0" diameter secondary - which I don't think is feasible.
>
> Sometimes I think I am on the verge of destroying my secondary at 6 kva.
>
> Ed Sonderman
>
>

```