Re: Neutrality of a battery; was Capacitor or condenser?

[William Beaty <billb@eskimo.com>]

On Sun, 6 Apr 1997, LUDWIK KOWALSKI wrote:


> c) William Beaty made a very convincing argument for the neutrality of
>    a source (see below) but I can not use it because I teach electricity
>    at rest before the electricity in motion. The idea of a constant 
>    current loop appears in chapter 17; while we are in chapter 16.

> From an engineering viewpoint, the net charge of an entire circuit is
ignored except in very specialized applications (such as electrometers.) 
Conventional circuitry is based on potential differences within the
circuit, rather than on potentential with respect to the rest of the
world.  It makes for an interesting analysis to examine a flashlight
circuit when it is charged to millions of volts with respect to earth, but
once students discover that the effects on the normal operation are
minimal, then one terminal of the power supply can forever after be
assumed to be neutral.  Pick one terminal and assume its grounded.

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