Q.Expand IGFET.

Field effect transistors are classified into two main families according to how the gate is coupled to the channel.

1. Junction FET (JFET) — the gate forms an ordinary reverse-biased pn junction with the channel. It is further divided into the n-channel JFET and the p-channel JFET.
2. Metal-Oxide-Semiconductor FET (MOSFET) — the gate is separated from the channel by a thin insulating oxide layer, so it is also called the Insulated Gate FET (IGFET). The MOSFET itself is subdivided into depletion-type and enhancement-type, each again available as n-channel or p-channel.

Knowing these expansions is a common one-mark exam task: FET = Field Effect Transistor, JFET = Junction Field Effect Transistor, MOSFET = Metal-Oxide-Semiconductor Field Effect Transistor, and IGFET = Insulated Gate Field Effect Transistor. …