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Re: Ohm's Law



Would we disallow the statement: "The resistance (R) of an incandescent
lamp varies with temperature." Ohm's LAW would make this an oxymoron -
how would you say it (concisely and usefully)?

The non-ohmic resistances of Mosfets (eg. for motor control) as a function
of gate input are important specs.

Both dynamic resistance (dV/dI) and DC Resistance V/I are useful
quantities, whether or not we speak of "Ohmic" materials.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "Herbert H Gottlieb" <herbgottlieb@JUNO.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, February 08, 2002 12:13 PM
Subject: Re: Ohm's Law


"that the resistance is independent of the voltage [temp, etc held
constant]" is a statement about a property of certain
particular materials.
For me, R=V/I merely defines the resistance of a current
path, in many
useful circumstances; the value of that R may be a function
of many things, including V.

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



The above wording may be a bit confusing. I believe that Bob meant to
say that "the resistance is independent of the voltage provided
that the temperature remains constant"

Herb Gottlieb