I am going to talk about the basic operation MOSFET.
MOSFET stands for metal oxide semiconductor field-effect transistor. Like any conventional transistor, it is a type of transistor with many applications in modern power electronics. Moreover, its functioning is based on how electricity flows through it. It is important to note that there are many variations in the uses of the MOSFET in different circuits. In MOSFET, the voltage applied to the gate region determines how much current flows from drain to source. And, this property gives MOSFETs their name Metal Oxide Semiconductor Field Effect Transistors. Interestingly, these transistors can amplify a signal or let only one specific kind of electric charge carrier through.
There are three basic types of MOSFETs.
The first type is the N-channel enhancement-mode MOSFETs or usually on (n-channel MOSFET). It allows current flow through the channel between drain and source even with zero input voltage applied across its terminals. Also, this means that it needs no gate signal for operation and hence is helpful in simple digital circuits.
The second type of MOSFETs are the N-channel depletion-mode or usually off (n-channel). This type requires a negative voltage for it to turn on and allow the flow of electric currents. Also, it has an advantage since this type of transistor acts as a resistor when it is off. Hence, very useful in specific applications that require control of input voltage.
Thirdly, the P-channel depletion-mode MOSFET transistor is usually off (p-channel MOSFET). This type blocks any current to flow through it unless a positive charge flows across its terminals. It means that this type of transistor acts as an insulator. Therefore, it is not suitable in specific applications where it is necessary to pass current at all times.