What are field effect transistors and their types?

Field Effect of Transistors (Field Effect Transistor, FET is a semiconductor device based electronic component that regulates the current by manipulating the carrier density in the semiconductor. It has three electrical levels: drain, source, and gate. Among them, a conductive channel composed of semiconductors is formed between the drain and source. By controlling the electric field of the gate, the number of electrons in the channel can be controlled, and then the current between the drain and source can be controlled.).

Transistors have the following characteristics:

High input resistance: Due to a large area of PN junction between the gate and semiconductor of a FET, the gate resistance is high, and the input resistance is high, usually from a few hundred M Ω to a few G Ω, which is much higher than a bipolar transistor.

Low noise: Due to the high input resistance, the noise of FETs is much lower than that of bipolar transistors, especially in low-frequency and high-frequency regions.

High bandwidth: Due to the high input resistance and small capacitance of FETs, they work better in high-frequency areas and have higher bandwidth.

Low power consumption: FETs have a particularly small output current and low power consumption, making them suitable for low power consumption.

Fast switching speed: FETs have fast carrier movement speed, so their switching speed is high.

High reliability: FETs have no moving parts, longer service life than bipolar crystal tubes, and stronger heat resistance.

Field effect transistors are divided into two basic types

N-channel field effect transistor (N-channel FET) The field effect between a transistor and a P-channel FET. In N-channel FETs, the conductive channel consists of N-channel semiconductors, but in P-channel FETs, the conductive channel consists of P-channel semiconductors. There are some differences in the working principles and applications of the two FETs, but the basic principles are the same.

FET is a commonly used semiconductor device, commonly used in amplification, switching, analog circuits, digital circuits, and other circuits. Compared with bipolar transistors, FETs have the characteristics of low noise, high input impedance, high gain, and low power consumption, so FETs have better performance in certain specific application scenarios.