Figure 8–1(a) shows the basic structure of an n-channel JFET (junction field-effect transistor).
Wire leads are connected to each end of the n-channel; the drain is at the upper end,
and the source is at the lower end. Two p-type regions are diffused in the n-type material
to form a channel, and both p-type regions are connected to the gate lead. For simplicity,
the gate lead is shown connected to only one of the p regions. A p-channel JFET is shown
in Figure 8–1(b).