Re: R = V/I ?

[Leigh Palmer <palmer@SFU.CA>]

> A final comment - I alluded earlier to the observation I've made on
> light bulbs that if you retrace by going down in V you won't necessarily
> follow the same I-V curve backwards.  If this is the case for your bulbs
> it should be possible to get a wildly scattered I-V plot by going up and
> down in V from various starting points, however all such points should
> follow the same smooth power vs temperature curve.  This gives added
> credibility to the power vs temperature curve being more
> fundamental/consistent than your I-V plot.

When I introduce RC charging in lecture I do a demo with a resistor and a
large capacitor. I replace the resisitor with a light bulb and repeat the
demonstration, showing both nonlinearity and hysteresis. I plot the Vc vs.
time curve for them using Vernier software. By this time the students are
ready for the additional complication involved.

Leigh