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Re: R = V/I ?

At 7:31 PM +0200 5/6/00, Mark Sylvester wrote:

But Leigh, would you not say that the (by now overworked) lightbulb has a
well-defined resistance given by R = V/I at every point on the I-V graph?

Actually, light bulbs (and other interesting devices) have TWO
resistances at each point on the I-V graph. The slope of the straight
line from the origin to the point in question is the 'usual'
resistance and the DYNAMIC resistance is the slope of the tangent
line at the point in question.

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