Re: delta V = I R

["Paul O. Johnson" <pojhome@FLASH.NET>]

Bob Sciamanda wrote:

> R can depend on many things, often usefully so, eg: photoresistive devices
> (like CdS) have light-sensitive resistance.  Bulk materials even have
> non-isotropic resistance (best described by a matrix).  An Ne2 neon bulb has
> almost infinite resistance below a firing voltage (c. 75 Volts), above which
> it is almost a short circuit.  A gas discharge can even have a negative
> DYNAMIC resistance (as can a tunnel diode).
>
> Some gas sniffing detectors rely on resistance changes in the presence of
> certain gases (often as the result of a chemical reaction.

Thanks for your reply, Bob. I am familiar with these devices, but when I asked
my question (admittedly not stated very well) I was thinking of carbon or wire
wound resistors.

poj