Field Effect Transistor (FET) is abbreviated as a field effect transistor. Conducted by a majority of carriers, it is also known as a unipolar transistor. It belongs to a voltage controlled semiconductor device. With advantages such as high input resistance (107~1015 Ω), low noise, low power consumption, large dynamic range, easy integration, no secondary breakdown phenomenon, and wide safe working area, it has become a strong competitor for bipolar transistors and power transistors.