Re: Breakdown voltage at submillimeter distances?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 09:40 PM 4/9/2006, Tesla list wrote:
> Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
>
> I thought air ionization/breakdown only happened above 315v?


Those are actually different phenomena...

Ionization will occur whenever the field is >30 kV/cm (approx), 
regardless of the gap and/ or voltage.

Sparks/breakdown depends on both the field and the gap length.

If you have a very short gap (or a very low density gas), you might 
not get sparks, but you might get a glow discharge or just plain old 
field emission.  In either case, current flows across the gap, it 
just doesn't form a spark or arc.




> Mike
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Sunday, April 09, 2006 5:42 PM
> Subject: Breakdown voltage at submillimeter distances?
>
>
> > Original poster: Robert Clark <bobbygc2001@xxxxxxxxx>
> >  Actually I'm interested in the results at a few
> > microns. I found this after a web search:
> > "Under constant atmospheric conditions, it is found
> > that the breakdown voltage of a uniform field gap may
> > be expressed in the form:
> >  V = A*d + B*SQRT(d)   where d is the gap spacing
> > [i.e., in centimenters - Bob]
> >  For air under normal conditions:
> >  A = 24.4kV/cm
> >  B = 6.29kV/cm^1/2"
> >  Anyone know if this formula would apply or know a
> > more accurate formula at the micron scale?
> >
> >    Bob Clark