Q.How many pn junctions are present in JFET?

A Junction Field Effect Transistor (JFET) is built around a bar of semiconductor that forms the channel, the path through which charge carriers flow. There are two types, distinguished by the channel material.

An n-channel JFET starts from a bar of n-type semiconductor. Two heavily doped p-type regions are diffused into opposite sides of the bar; these two regions are joined internally and brought out as a single gate terminal. The n-type strip lying between them is the channel, and its majority carriers are electrons, which carry the current. Ohmic (non-rectifying) contacts at the two ends of the bar form the drain and the source.

A p-channel JFET is the material-swapped mirror image: a p-type channel bar with two n-type gate regions on its sides. Here the majority carriers are holes. …