I have an assortment of T1 and T1¾ LEDs from sampler kits and beginner kits. The kits have sketchy documentation, with missing or inaccurate part numbers. I was able to track down datasheets for some of them, like the “WP7113HD” and the “L934LID.” For others, all I have is a description like “Violet Hi-Br Clear.” So I have several LEDs with a missing or questionable datasheet. It looks like they all of the LEDs expect 2mA, 10mA, or 20mA forward current, but I’m not sure which are which.
Another complication is that some of the datasheets are ambiguous about the intended forward current. For example, the WP7113ID datasheet specifies luminous intensity relative to IF=10mA, but most of the optical and electrical characteristics are given for IF=20mA. So even with the datasheet, I’m not sure whether that LED is supposed to be driven at 10mA or 20mA.
How should I choose a forward current for these LEDs? What will happen if I get it wrong and drive a 2mA LED at 10mA, or a 10mA LED at 20mA? I think they are all safe for up to 25–30mA, but I suspect that it’s not a good idea to overdrive them.