I bought the lm317t from radio shack. It shows on the package that 2 is the out or the middle pin. As the picture goes I think with the pins pointing down looking at the thing with the heat sink part laying on the table pin 3 is on the left and then pin 2 is center and pin one is right. Here is the schematic of my power supply, only I have a 25 v 450 ma transformer. I had it working for a minute and put a meter on the output and the fuse blew. I tried again after checking it and it blew as soon as i turned it on.