Two methods are described to obtain the value of the series resistance

of a Schottky diode from its forward I-V characteristic. The value of

is then used to plot the curve ln (

) versus

which becomes a straight line even if ln

versus

does not. The ideality factor

and the Schottky-barrier height

of the diode then follow from the standard procedure. The main advantages of the methods are: 1) a linear regression can be used to calculate the value of

, 2) many data points are used over the whole data range which raises the accuracy of the results, and 3) the validity of constant

assumption can be checked by the linearity of the ln

versus V
Dcurve. The methods are illustrated on the experimental data of a real diode.