For an NMOS transistor to be used as an effective amplifier, it should be biased in which region of operation?
The saturation region is where the transistor acts as a voltage-controlled current source. In this region, the drain current (Id) is strongly controlled by the gate-source voltage (Vgs) and is relatively independent of the drain-source voltage (Vds). This behavior provides high voltage gain, which is the fundamental requirement for an amplifier. In the triode region, it acts like a voltage-controlled resistor, and in the cut-off region, it is off (no current flows).
