Re: Gap Question

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Luke,

I not that the total (or static) resistance of the gap is negative, but if
you look at its VI curve, it has negative slope when the gap fires.  Plot
voltage on the x-axis and current on the y-axis.  You start raising the
voltage across a non conductive gap (with a current limited supply set to
low current, high enough to keep the gap conducting) upto but just before
firing, the current is zero.  Now raise the voltage to breakdown and all of
a sudden, current flows and the voltage snaps back to a low voltage and the
current flowing is the current limit of the supply.  Now raise the current
limit and the voltage across the gap decreases.  At some current level, you
have minimum gap voltage.  If you raise the current limit anymore, the
voltage starts rising again.  For the portion of the VI curve that snaps
back and to this minimum voltage point the slope of the VI curve is negative
and hence the negative dynamic resistance.

Gerry R


 > Original poster: "Luke" <Bluu-at-cox-dot-net>
 >
 > Holly cow that did throw a bit of a wrench in there.  My gears just
 > stopped.  That is hard to conceptualize based on im so used to the ohms
 > law concept being so natural to me that it is very hard to imagine a
 > negative resistance.  Not sure how to go about wrapping my head around
 > that one.
 >
 > Luke Galyan
 > Bluu-at-cox-dot-net
 > http://members.cox-dot-net/bluu
 >