Re: Gap Question

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

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:

 > 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.

The negative resistance characteristic appears in any device that can
first sustain a high voltage without conduction and then suddenly
starts to conduct, while the voltage drops. The current x voltage
characteristic is something as:

|i      *
|     *
|   *
| *
| *
|  **
|    **
|      *    v
+******------

There is a region where the inclination of the curve is negative.
This happens in spark gaps, gas-discharge lamps, pnpn diodes, etc.
The curve is similar, reflected, for negative voltage and current.
Note that the negative (incremental) resistance doesn't last for
any value of current, and that the power dissipated in the element
is always positive.

Antonio Carlos M. de Queiroz