Re: electronic components

["Daniel L. MacIsaac" <Dan.MacIsaac@nau.edu>]

According to Crane, 0.5 sec HALF discharges the cap.  This doubles an already
tiny resistance to something else too tiny, I think. 

I think the cap has a nonlinear internal resistance as the amount of 
charge that can flow is physically restricted by the internals of the cap, 
meaning that I is restricted by factors other than V (like charge depletion
in a real battery).  This restriction may also depend on the amount of 
charge presently stored, which I believe is a hysteresis effect for these
caps.  I may be way out of line and would appreciate someone more 
knowledgeable than I pointing out the errors in my ways, preferably 
someone with data from a supercap...

Dan M
 
PS 5Tau from 7Tau?  Doubtless this is a case of caving-in to todays'
shiftless students.  My grampy used 15Tau, walked to school barefoot uphill
both ways and his class average was H.  :^)  Grade inflation strikes
cap discharging.  I wonder how many Tau the Japanese and Germans are using??



> While it is only a small factor, I'll note anyway that the "time to
> discharge of a capacitor" is generally considered (read stated in most
> books) to be about 5 time constants.  This would make R*C~0.1s (=0.5s*1/5) 
> and therefor (if C~1F) R~0.1ohms.
>
> BTW: When I was a young student (~1960), the time to discharge was
> considered to be about 7 time constants.  I'm not sure why the change!? 
>
>
> On Wed, 18 Dec 1996 kowalskil@alpha.montclair.edu wrote:
>
> > If 1/2 second is needed to discharge a supercap then R*C is about 1/6 s.
> > If C=1F then R=1/6 ohms. Yes, this is significant but not really very large.
>
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