"Rich Webb" wrote in message
...
On Wed, 11 Jul 2007 01:34:57 GMT, Rich Grise wrote:

I've just salvaged some LEDs - here's one:
http://mysite.verizon.net/richgrise/...-green-LED.JPG

and I'm wondering if anybody knows how to tell from the shape of the
leadframe parts, which is the cathode and anode? (I'm also rather
proud of the photo. ;-) ) Neither of my ohmmeters even makes it conduct;
I'll probably have to set up a little tester, but I thought it was kinda
cool the way the leads hold the chip and so on.

The other guys have already given you the clues that work for almost
all of the leaded LEDs out there. For the exceptions (and to help
matching color/brightness) this little gizmo is cheap enough to be
handy. (Jameco is just one source)
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=355805


Another simple polarity tester is a 9V PP3 with your body as the
current-limit resistor. You may need to lick your fingers, but there's no
risk of a reverse voltage damaging the LED.