#### dkace

##### Full Member level 6

When the MOS is entering the saturation region, we say that the channel is closed in the drain side. And as the drain voltage is increasing, the current is remaining fairly stable - with a small slope.

Ok, I understand the mathematics. Can anyone explain it in plain physics? If the channel is closed to a pin or is closed -period, how can current go through and we modelized it as stable? Is the channel really closed or we asume that a small path is left that can't be closed any more? Meaning that although we had a small resistance increasing with the increase of the drain voltage, this is the maximum resistance we will have?

And if so, why all odels refer to this as " closing of the channel"?

Can anyone decribe it from a physisist point of view?

Thanks,

D.