Field-effect transistor, commonly known as FET, is a transistor device used to amplify weak signals, switch direct current, or perform as an oscillator. It is a voltage-controlled device that uses the applied voltage to control the flow of current and is characterized as a unipolar transistor as it uses a single carrier. The input impedance of FET is generally high for all forms and types, making it an attractive choice for many applications.
Main Components of FET
FET transistor has three main components: the source, drain, and gate. The source is where most of the charge carriers enter the device, and the drain is where they exit. The gate is the terminal internally connected to two terminals and controls the conductivity of the channel between the source and the drain.
Types of FET Transistors
The basic types of FET transistors are quite different from BJT transistors. FETs are semiconductor devices with three terminals: the source, drain, and gate. There are two types of FET transistors: majority carrier devices and minority carrier devices. Majority carrier devices absorb current primarily through majority carriers, while minority carrier devices carry current mainly through minority carriers.
Applications of FET Transistors
FET transistors have various applications, including amplifiers, switches, and oscillators. They are widely used in audio and radio frequency amplifiers, voltage-controlled resistors, mixers, and other frequency control devices.
How does the FET transistor work?
FET is a voltage-controlled device that uses the applied voltage to control the flow of current by creating an electric field in the channel through which the current flows. By varying the voltage applied to the gate, the conductivity of the channel between the source and the drain can be controlled.
What is the difference between FET and BJT transistors?
The basic operation of FET and BJT transistors is quite different. FET transistors use voltage to control the flow of current, while BJT transistors use currents to control current flows. FETs are considered unipolar transistors as they use a single carrier, whereas BJT transistors are bipolar transistors, using both electrons and holes as charge carriers.
In conclusion, the FET transistor is a valuable semiconductor device with various applications in amplifiers, switches, and oscillators. Understanding the excellent features and uses of FET can help engineers optimize their electronic circuits to achieve better performance, efficiency, and accuracy.