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.