Week 10
MOSFET Operation and Bias
I organize a study path from diodes to single-transistor amplifiers in the order that makes the circuit behavior easiest to revisit.
What I connect in this unit
A MOSFET forms a channel after VGS exceeds threshold voltage, behaves like a voltage-controlled resistance in the triode region, and enters saturation when VDS exceeds the overdrive. Body effect shifts threshold when source and body potentials differ.
Concept map
- Threshold voltage
- Triode region
- Saturation region
- Body effect
Technical anchor
In the long-channel approximation, saturation requires VDS ≥ VGS − VTH and ID ≈ 0.5kn(VGS − VTH)².
How I review it
Given VGS and VDS, identify cutoff, triode, or saturation before calculating current, and examine the threshold shift from body effect when the source rises above the body.
Connection to the full course
Unit 10 of 12. Unit numbers form a concept-study sequence and do not claim the original class schedule.