Re: Ohm's Law

[Bob Sciamanda <trebor@VELOCITY.NET>]

I always treat it as the definition of resistance.  In like manner dV/dI
is the definition of dynamic resistance.  I call neither a "law";  to me
they are definitions of useful quantities.  The statement that R is a
constant might be called Ohm's law, obeyed - within limits and under
certain constraints - by some materials.  But Ohm's law cannot say
anything about resistance until resistance is first defined.  To lump both
the definition and the law in a single relation is either redundant or
contradictory, and certainly wasteful of notation, and confusing.

Bob

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----
From: Van E. Neie <ven@PHYSICS.PURDUE.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, November 08, 1999 9:34 AM
Subject: Ohm's Law


> Is there any advantage to calling *V = IR Ohm's Law?  I have found that
> just calling it a fundamental relationship among *V, I and R is
> sufficient.  If you know two of these variables, you can find the
> third.  Whether the device is ohmic doesn't matter, right?
>
> Am I missing something?  The only reason I bring it up is that
> practically every elementary physics text refers to it as Ohm's Law, but
> often there is no mention of the conditions that must be satisfied.
>
> Thanks.
>
> --
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