The black antic static foam that protects ic's is a good example of such a
resistive material.   Would be interesting to measure resistance across it
and then cut off pieces to narrow path while logging resistance.

Also, this stuff will change resistance when compressed.  So it could be
used as a push thingee and maybe even give a degree of how hard it was
pushed.  Would it be possible with more than one resistance probe connected,
to determine the xy position of the push?

Bill

----- Original Message ----- 
From: "Robert A. LaBudde" <ral@lcfltd.com>
To: <piclist@mit.edu>
Sent: Friday, October 21, 2005 7:09 AM
Subject: [EE] Resistance between 2 points of a uniform material


> I have a theoretical question to ask.
>
> Consider an infinite plane of a uniform resistivity material (e.g.,
> conductive foam).
>
> Take two points A and B a fixed distance apart in this plane:
>
> <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^>
> < >
> < A B >
> < >
> <vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv>
>
> How, using techniques of electrical engineering, can the resistance in
ohms
> be calculated between points A and B?
>
> Obviously it can be measured easily in practice by simply placing one
> ohmmeter probe at A and the other at B. But how could it be calculated
from
> theory?
>
> It would seem this problem should be easy, similar to EMF field
> calculations for potential difference, etc., however it's not obvious to
me
> as to how this could be done.
>
> Any suggestions or experience?
>
> The importance of the theoretical analysis is obvious: It allows answers
to
> questions about parametric dependence on length and width of a finite
> rectangular piece, extends to non-uniform resistivity, etc.
>
> ================================================================
> Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral@lcfltd.com
> Least Cost Formulations, Ltd.            URL: http://lcfltd.com/
> 824 Timberlake Drive                     Tel: 757-467-0954
> Virginia Beach, VA 23464-3239            Fax: 757-467-2947
>
> "Vere scire est per causas scire"
> ================================================================
>
> -- 
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist