2. Operation of the ideal transistor

Before turning to the mathematical model of a MOS transistor, we'll develop the notion of threshold voltage (V _th threshold voltage); this is one of the most fundamental notions for a TMOS, as it governs the transistor's turn-on (sometimes, V _th is also called turn-on voltage).

Next, we'll explain the physical principle behind TMOS modeling, based on Ohm's law. This will easily lead us to the mathematical model.