An example method provides a power MOSFET, a voltage source coupled to the power MOSFET, and a current measurement device coupled to a first non-control terminal of the power MOSFET. The voltage source, the current measurement device, and a second non-control terminal of the power MOSFET couple to ground. The method uses the voltage source to apply a voltage between a gate terminal and the second non-control terminal of the power MOSFET, the voltage greater than zero volts and less than a threshold voltage of the power MOSFET. The method also uses the current measurement device to measure a first current flowing through the first non-control terminal while applying the voltage. The method further uses the first current to predict a second current through the first non-control terminal for a voltage between the gate terminal and the second non-control terminal that is approximately zero.