So, LM317 can be used as a constant current regulator by adjusting the voltage in the
Adj pin. The internal voltage reference is 1.25V, and so using a 1.25/0.900 ~= 1.4Ohm resistor and a constant current source of 12v, one would output a constant current of 893mA.
At least in theory, and according to every site I read on the internet; however, I just did that and measured the current passing to the led: approx. 200mA!
What am I doing wrong?
Addendum: I'm using these type of leds, and I'm measuring the current passing between the limiting resistor R1 and the LED1.