I'm trying to build a circuit to drive a laser diode that has an operating voltage of 3V and operating current of 180mA-250-mA. I have built the below circuit referencing Figure 14 in Section 9.3.3 in http://www.mouser.com/ds/2/405/lm317-556636.pdf. I know I still need to adjust the voltage, but I am puzzled as to why my ammeter is indicating such low current. It will not even light an LED. The 12V DC source is from a wall wart and can source 3A. Any insight on what I'm doing wrong?