In a field-effect transistor (FET), the width of a conducting channel in a semiconductor and, therefore, its current-carrying capability, is varied by the application of an electric field (thus, the name field-effect transistor). As such, a FET is a “voltage-controlled” device. The most widely used FETs are Metal-Oxide-Semiconductor FETs (or MOSFET). MOSFET can be manufactured as enhancement-type or depletion-type MOSFETs. Another type of FET is the Junction Field-Effect Transistors (JFET) which is no