That's correct, the "top" or "tab" of the lm-317 is connected to output voltage.
Here's a link to a data sheet: http://www.national.com/pf/LM/LM317.html
73
WB8KRN


"R.M" wrote in message ...
ammo can. The problem is, the "top" of the lm317 that you attach the
heat sink to has positive voltage on it. Its the same voltage as the
output pin on the lm317. Is this normal? So when I connected the lm317
to the ammo can(not knowing the problem) its created a short and the
lm317 really really hot. I just assumed that the "top" of the lm317
would work if it was grounded, but l was wrong. Am I missing something
or is this normal. As long as I either unhook the lm317 or the bulkhead
BNC connector from the can everything works great. Any comments.