METHOD OF MEASURING A DEVICE PARAMETER

For example, a method of measuring a device parameter includes: a step of repeatedly measuring the gate-source voltage (or gate-emitter voltage) of a switching element in its switching transient state while switching the external gate resistance for the switching element among m resistance values (where m is an integer of three or more); and a step of, while representing the internal gate resistance and the plateau voltage of the switching element by Rgin and Vp respectively and using the m resistance values of the external gate resistance and corresponding m voltage values of the gate-source voltage (or gate-emitter voltage) as Rg(k) and Vgs(k) respectively (where k=1, 2 . . . m), performing the fitting of the equation Vgs(k)=Rg(k)/(Rg(k)+Rgin)×Vp, thereby to derive the internal gate resistance Rgin or the plateau voltage Vp of the switching element.