MOSFET Working Principle? What are the Main Parameters? Detailed Explanation

The MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) is a semiconductor device composed of a structure made of metal, oxide, and semiconductor crystal.

**Working Principle:**
When a certain voltage is applied to the gate of the MOS tube, an electric field is formed, which changes the conductivity of the semiconductor. This leads to a variation in resistance between the source and drain, enabling the modulation and control of current.

**Main Parameters:**
1. Static Operating Point: Source-drain current, gate voltage;
2. Dynamic Parameters: Maximum drain current, maximum drain voltage, maximum power dissipation, switching time, and duty cycle, among others.

**Detailed Explanation:**
The static operating point refers to the working point of the MOS tube when the current between the source and drain is zero under a specific voltage. Generally, the static operating point specified by the manufacturer is the most suitable. Deviating from this point may affect the performance of the MOS tube.

Dynamic parameters refer to the characteristics of the MOS tube under dynamic operating conditions. The maximum drain current is the highest current the MOS tube can withstand. Exceeding this value may cause damage. The maximum drain voltage is the highest voltage the MOS tube can tolerate, beyond which breakdown may occur. The maximum power dissipation is the maximum power the MOS tube can handle; exceeding this limit may lead to overheating or even failure. Switching time refers to the time required for the MOS tube to transition from the off state to the on state, while the duty cycle is the ratio of the off time to the total time. These parameters require special attention in certain applications.

In summary, the MOS tube is a commonly used semiconductor device. Its main parameters include the static operating point and dynamic parameters, and it is essential to select the appropriate MOS tube model and parameters based on the specific application scenario.