I've been trying to learn about transistors, but there's something that's confusing me. What are the differences between a JFET and a depletion mode MOSFET, based on how they are used? They seem very similar to each other.
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JFETs and depletion mode MOSFETs are both three-terminal devices used for amplification and switching applications. JFETs are constructed by forming a PN junction between a channel of semiconductor material and two regions of opposite doping, while depletion mode MOSFETs are constructed by creating a channel of semiconductor material between two heavily doped regions of the opposite type, with a thin layer of oxide and a gate electrode on top.

The operating principles of JFETs and depletion mode MOSFETs differ in that the current flow between the source and drain terminals of a JFET is controlled by the voltage applied to the gate, which in turn controls the width of the depletion region around the channel. In a depletion mode MOSFET, the gate voltage attracts mobile carriers to the interface between the channel and the oxide layer, thereby depleting the channel of carriers and increasing its resistance. JFETs have a high input impedance and low noise level, while depletion mode MOSFETs have lower input impedance but can provide higher gain and faster switching speeds.
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