Field Effect Transistor

A Junction Field Effect Transistor (JFET) is a three-terminal semiconductor device that controls current flow through a channel using an electric field. Unlike bipolar transistors, JFETs are voltage-controlled devices where the gate voltage controls the conductivity of the channel between the source and drain terminals. They are normally-on devices that conduct current when no gate voltage is applied, and current decreases as reverse gate voltage increases. JFETs are commonly used in low-noise amplifiers, analog switches, and high-input impedance circuits due to their minimal gate current requirements.

A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a type of transistor that acts as an electronically controlled switch or amplifier. It uses an electric field applied to a gate terminal to control the flow of current between its source and drain terminals, with virtually no current flowing into the gate itself. MOSFETs are fundamental building blocks in digital circuits, power electronics, and integrated circuits due to their high switching speed, low power consumption, and excellent on/off characteristics.