Brief Relationship Between MOSFET Current and Voltage?

In MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), there is a specific relationship between current and voltage. The current in a MOSFET is related to the gate voltage and the drain voltage, which can be described by the following key parameters:

1. Threshold Voltage (V_th): When the gate voltage is greater than or equal to the threshold voltage, the MOSFET begins to conduct. Below V_th, the MOSFET is in the cutoff state, and the conduction current is very small.

2. Turn-On Voltage: When the gate voltage exceeds a certain value, causing the MOSFET to fully conduct, current begins to flow through the channel. This voltage is commonly referred to as the turn-on voltage or saturation voltage.

3. Saturation Current: The maximum current value achieved when the MOSFET is fully conducting. In the saturation region, the drain voltage has a relatively small effect on the current, and the current hardly changes with variations in the drain voltage.

In summary, the conduction and cutoff states of a MOSFET are primarily controlled by the gate voltage, while the magnitude of the current depends on the voltage difference between the gate and drain, as well as the internal characteristics of the MOSFET (such as holding current, field-effect mobility, etc.).