Based on the circuit from this page called transconductance amplifier, I decided to build an adjstable constant current source for up to 1.6A:
Current is set by the voltage divider connected to the op-amp input: Iout=Vdiv/Rlim
On Multisim it works fine, however, in real life the current keeps drifting from this value, and the 5k pot does nothing.
I tried swapping the op-amp inputs and then the current starts high, slowly going down to the desired value, but in both cases the FET is heating too much. Is this design correct?