[Physics] Resistivity of non-ohmic resistor

electrical-resistance

In layman's terms, how do you determine the resistivity constant of a non-ohmic material having measured voltage and current?

I understand that non-ohmic materials don't follow Ohm's Law, but will this still be able to be used to determine the resistance? Otherwise how can I determine an initial resistivity in order to use R=[rho]l/A to figure out the resistivity?
Is there a different formula for this circumstance, or will I need to collect more data?

(Yeah, even I know it's a totally dumb question)

Best Answer

It is not a dumb question.
The gradient of the voltage against current a at given voltage is called the incremental/dynamic/small signal resistance.
This enables you to find out how small changes in voltage/current affect the current/voltage around the voltage where you measured the gradient.
So from this incremental resistance you can define an incremental resistivity but I am not so sure as to what you would use it for.