Power-law nature of field-effect transistor experimental characteristics

In making experimental measurements of field-effect transistor static drain characteristics in the pinch-off region, determination of the effective pinch-off voltage is not possible by direct measurement because of the presence of spurious drain current at and beyond pinch-off. Further, indirect measurement is hampered by the absence of a theoretical straight-line function from which the pinch-off voltage may be obtained as an intercept or a slope. In this communication a power-law relation for the transfer characteristic is assumed, from which values of both the pinch-off voltage and the exponent may be obtained directly from a straight-line plot of experimental quantities