Bought a bunch of coloured 2mm LEDs from lighthouseleds.com a while back and after soldering some into a custom PCB I found some that wouldn't light. I thought maybe I might've over-voltaged them by accident, or got a few bad'uns, but when I desoldered and tested them I found the leads were reversed - usually, the shorter lead is the cathode (-ve) and the plastic lens is flat on that side, but on some of these they were reversed (+ve lead was shorter and on the flat side). From the same order!
Anyone else ever encounter this? I will have to whip up a 2V/3V LED polarity tester before I solder any in from now on.
LighthouseLEDs.com and Reversed Polarity of Leads
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