Re: Minimum arc voltage of air was: Definitions of High Voltage

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Kidd6488-at-aol-dot-com>

Somebody should try this.  You could rig up some fine thread bolts as
electrodes, and hook up a variac with a DMM to a 12kV neon (12kV units are
1:100) and feed it 34.00 volts. I may try this, but not for a little while.

---------------------------------------
Jonathon Reinhart
hot-streamer-dot-com/jonathon

>
> >
> > Interesting is the fact that bellow 300-400 V in a
> > very narrow gap there is still no gas discharge before
> > metal to metal touch (standard atm. conditions).
>
> Yes, it is interesting. North states that 340 is the "absolute minimum"
> (in air), therefore, anything below this value should not arc a gap
> regardless of eletrode size, shape, gap distance, or barometric
> pressure. He goes on to say that breakdown voltage decreases as pressure
> decreases until the 340V minimum is reached, due to the fact that as the
> melocular density of air is reduced, there is greater likelihood that a
> free ion can traverse the space between electrodes without running into
> something. But (here's the thing), as pressure is further reduced, the
> required voltage for breakdown increases once again because a more
> limited number of air molecules make ionization more difficult. So, we
> have a dip and it's value is 340V. Thus, it's the physical makeup of air
> and pressure that give us this minimum voltage.
>
> Take care,
> Bart