<aside> 💡 网上各种FET的标号和原理我觉得写的都各种不靠谱和混乱。我自己总结了一下，大部分来源于The Art of Electronics。

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Field-effect transistor (FET)

n-channel FET(conduction by electronss) analogous to npn bipolar transistor

p-channel FET(conduction by holes) analogous to pnp bipolar transistor

FETs can be made with two different kinds of gates(thus JFETs and MOSFETs) and with two different kinds of channel doping(enhancement and depletion modes).

— n-channel enhancement-mode mosfet which is analogous to the npn bipolar transistor.

The gate of the MOSFET is trely insulated from the drain-source channel; thus, unlike the situation for bipolar transistors(or JFETs), you can bring it ositive(or negative) at least 10V or more without worrying about diode conduction.

The FET differs from the bipolar transistor in the so-called linear(low-voltage) region of the graph, where it behaves rather accurately like a resistor even for negative Vds; this tours out to be quite useful because the equivalent drain-source resistance is, asyou might guess, programmed by the gate-source voltage.