Re: spark gap

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

Original poster: David Speck <dave-at-davidspeckmd-dot-org> 

Jimbo,
Carbon rods are not effective for spark gaps.  One they heat up, they 
provide carbon vapor which makes the gap conduct very easily, and thus 
provide very poor quenching.  The carbon arc would essentially be a short 
circuit, and would never allow your primary cap to charge up to its maximum 
voltage.

That's the same reason you wouldn't want to use needle point electrodes, 
either.    An ideal spark gap would have very low resistance for a short 
period, then go to infinite resistance to break the circuit after the cap 
is discharged to allow the recharge cycle to begin again.  Rotary gaps come 
close to this behavior in that the electrodes give a very short arc length 
when the gap is closed, and then move to a very long arc length to break 
the arc to let the cap recharge.

HTH,
Dave

Tesla list wrote:

>Original poster: Jimbo07031982-at-aol-dot-com
>would  carbon rods be sufficient for a spark gap