- #1

morrw1ndy

- 4

- 0

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1. Homework Statement

1. Homework Statement

How to determine the change of R of a non-ohmic conductor from different parts of I-V graph?

Please see the sketch attached.

## Homework Equations

R=V/I

## The Attempt at a Solution

For the part that passes through the origin, it is obvious that the reciprocal of the gradient, i.e. dV/dI, shows how R changes.

However, for the upper part(green part), since it does not passes though (0,0), the gradient only shows how I changes with V, but not how R changes with V.

I have tried to sub in numerical values as shown in the second picture, it seems that R varies in different ways even though I-V graph is concaving downwards.

Instead of sketching a separate R-V graph, are there any alternatives to tell the change in R directly from the graph?

Thanks a lot.