Charge control of field effect transistors

The drain current of a junction field effect transistor can be directly related to the charge on the gate terminal. For a device operating in the saturated region, the drain current is very nearly a linear function of the gate charge. As a result, if the conventional drain characteristics are re-drawn with curves of constant gate charge replacing curves of constant gate voltage, the characteristic curves will become uniformly spaced for equal increments in gate charge. This characterization can be useful to both user and designer of junction FET´s.