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JFET (Junction Field-Effect Transistor) – N-CHANNEL or P-CHANNEL

JFET (Junction Field-Effect Transistor) – N-CHANNEL or P-CHANNEL

The junction gate field-effect transistor (JFET or JUGFET) is one of the simple type of field-effect transistor.[1] JFETs are three-terminal semiconductor devices that can be used as electronically-controlled switches, amplifiers, or voltage-controlled resistors. Unlike bipolar transistors, JFETs are exclusively voltage-controlled in that they do not need a biasing current. Electric charge flows through a semiconducting channel between source and drain terminals. By applying a reverse bias voltage to a gate terminal, the channel is "pinched", so that the electric current is impeded or switched off completely. A JFET is usually ON when there is no potential difference between its gate and source terminals. If a potential difference of the proper polarity is applied between its gate and source terminals, the JFET will be more resistive to current flow, which means less current would flow in the channel between the source and drain terminals. Thus, JFETs are sometimes referred to as depletion-mode devices.