i have tried a Red, a green and a UV
and for the pot... it's odd... when i measure the resistance i get from 384 Ohm to 10k, nothing below 384... crap...
and since the 431 has a 2.5v Reference i cannot go below that right? Hence why the led voltage drop has to be higher?
Or is it all due to the configurations of the resistors?
found a Green led now while writing this, measured with diode setting on multimeter it said 1.9 and then straght to 1. (out of range) maybe it'll work?