When used as a transconductance amplifier with the source as the input and the gate grounded. Is the internal impedance of a mosfet linear? Does it act as a perfect resistor divider with the load or do the transfer curves come into play?

 

Large signal transfer curves definitely.

Small signal take a look at this -

https://www.google.com/url?sa=t&rct...ecture23.pdf&usg=AOvVaw1MpL2UiazZMUkXJDcCopbP

Regards, Dana.

 

If I servo correct the source of the mosfet to have a stable voltage in this scenario is that the same as linearizing the internal resistance?

 

So you are varying Vgs by pulling down on the source. This has the same effect as Varying Vgs with source grounded.
Look at Id vs Vgs. There is usually a linear region but the curves cannot be relied upon to give a an accurate impedance value.
Mosfets are not great at linear V/I conversion.

What is it you are trying to achieve with your Mosfet circuit. Can you show us your intended circuit- If not we cannot help.