A method of measuring semiconductor output characteristics is provided that includes connecting a pulse generator to the gate structure of a semiconductor device, and applying a plurality of voltage pulses at least some of which having a different pulse width to the gate structure of the semiconductor device. The average current is measured from the drain structure of the device for a duration of each pulse of the plurality of pulses. From the measured values for the average current, a self-heating curve of the average current divided by the pulse width is plotted as a function of the pulse width. The self-heating curve is then extrapolated to a pulse width substantially equal to zero to provide a value of drain current measurements without self-heating effects.