As a nonlinear diode-voltage electricity have changed the resistance when the individual values ädern. Here one speaks of a differential resistance, this corresponds to the slope of the tangent point of concern on the curve.



The differential resistance is calculated from

 

Here we take the work of a point A diode.




Then follows:





Still must be taken into account that, when rising currents of resistance is always smaller. To be a correct resistance to calculate, must also train resistance RB taken into account.