**Created: 2023-07-29** - Great for high current requirements where pulling current from something like a microcontroller isn't feasible (voltage controlled current source in its saturation region). For instance, it can act as a buffer between a PWM signal and an LED - Low $R_{ds}$ means higher currents without a lot of power loss in the form of heat ### Channel length modulation effect - NMOS/PMOS transistors suffer from this effect where the drain current $I_D$ is not constant in the saturation region and depends on the applied drain-to-source (in the case of NMOS) and source-to-drain (in the case of PMOS) voltage. ($V_{DS}$ or $V_{SD}$) - There is a device parameter $\lambda$ and a quantity known as the early voltage $V_A$ that determines the value of the drain current. The expression for an NMOS transistor looks like this: $I_{D} = \frac{1}{2}k_n(V_{GS} - V_{tn})^2(1+\lambda V_{DS})$ - The best MOSFET explainer: https://youtu.be/AwRJsze_9m4?si=_9baR9JceqDX32Ui ### Difference between an N channel and a P channel MOSFET -