Hi,
I am trying to understand some of the basics of how the mosfet amplifies. Specifically, n channel depletion mode mosfet.
I understand it happens after the drain voltage reaches pinch off. But I am not entirely sure why after this point it is that there is so much gain for small increases in gate voltage.
I am not sure if it contributes to the "gain" but correct me if I'm wrong, after the mosfet reaches pinch off voltage and enters saturation, whilst it is amplifying the gate voltage, the channel length is also modulated?
Is it this effect that is causing the amplification? The width of the depletion layer between the n+ region connected to drain and the channel is being modulated? If so why exactly does it cause gain?
Or am I wrong about the channel length modulation part?
I am not looking for equations per se, but rather a sort of physical intuitive explanation.
EDIT: Following on from this idea (if it is correct), the voltage caused by the depletion layer between the n+ region connected to the drain and the substrate is somehow proportional to the gain?
I am trying to understand some of the basics of how the mosfet amplifies. Specifically, n channel depletion mode mosfet.
I understand it happens after the drain voltage reaches pinch off. But I am not entirely sure why after this point it is that there is so much gain for small increases in gate voltage.
I am not sure if it contributes to the "gain" but correct me if I'm wrong, after the mosfet reaches pinch off voltage and enters saturation, whilst it is amplifying the gate voltage, the channel length is also modulated?
Is it this effect that is causing the amplification? The width of the depletion layer between the n+ region connected to drain and the channel is being modulated? If so why exactly does it cause gain?
Or am I wrong about the channel length modulation part?
I am not looking for equations per se, but rather a sort of physical intuitive explanation.
EDIT: Following on from this idea (if it is correct), the voltage caused by the depletion layer between the n+ region connected to the drain and the substrate is somehow proportional to the gain?
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