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From: myers@hpfcdj.HP.COM (Bob Myers)
Newsgroups: sci.electronics
Subject: Re: DC motor noise in audio circuit
Message-ID: <17660093@hpfcdj.HP.COM>
Date: 30 Aug 90 17:47:26 GMT
References: <15857@s.ms.uky.edu>
Organization: Hewlett Packard -- Fort Collins, CO
Lines: 16

>Remember, magnetic fields don't really induce voltages in isolated bits
>of paths. High impedance, low impedance, it doesn't matter. Magnetic fields
>induce voltages in *loops*.

Minor not: magnetic fields induce *current* in loops, which then by Ohm's
law may result in potential differences ("voltage") *across* any two points
on the loop, by the resistance of the loop.

I know *you* know this, Jeff, but I get too many students who talk about
"the voltage through this resistor" and other such abominations to let it
go uncorrected.


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
myers@fc.hp.com                          |  sentient life-form on this planet.