Simple Question...

Kurt_ · Post by **Kurt_** » Thu Feb 02, 2006 6:44 pm

In regards to LED's, what is a "test current", and what is the optimal current for an LED based on the test current? (If you can do a calculation based on the test current, like optimal current is 200% of that or something.)

The LED's I own have a test current of 20mA. But that means nothing to me. Please help.

Wakefire · Post by **Wakefire** » Fri Feb 03, 2006 2:16 am

Be a little more specific please. What do you mean? Like you wanna know how to test if the LED works? Or do you wanna know the best current and voltage to operate at.

cennar · Post by **cennar** » Fri Feb 03, 2006 4:23 am

i think he wants to tes there fella. lol im drunk

timmeh87 · Post by **timmeh87** » Fri Feb 03, 2006 9:06 am

cennar, are you ever really sober?

anyways kurt... what the ben heck are you talking about.

Kurt_ · Post by **Kurt_** » Fri Feb 03, 2006 3:30 pm

Well, for the LED's I got, it specifies a "test current" of 20mA. I want to know what a test current is. And if it is run at a lower current than the optimal current for the LED's.

cennar · Post by **cennar** » Fri Feb 03, 2006 4:01 pm

sober cennar: what you want to test how low it can go?

Kurt_ · Post by **Kurt_** » Fri Feb 03, 2006 4:15 pm

GAHHHHHHH!!!!

Nevermind!

Wakefire · Post by **Wakefire** » Sat Feb 04, 2006 2:04 am

Nice multiple use of hulk pictures in a short period of time

A.J. Franzman · Post by **A.J. Franzman** » Sat Feb 04, 2006 2:53 am

Kurt_ wrote:Well, for the LED's I got, it specifies a "test current" of 20mA. I want to know what a test current is. And if it is run at a lower current than the optimal current for the LED's.

That's probably the current at which the forward voltage drop of the LED was measured. Maybe also the recommended constant DC operating current. It would be really helpful if you could give us a link or show us an image or something, of the specs you're writing about.

Kurt_ · Post by **Kurt_** » Sat Feb 04, 2006 11:24 am

[/img]http://www.dialight.com/productSpecs.cf ... er=5219901

I would THINK test current is the current that they either...

a) Test it to make sure that it works. In this case it would be much lower than the current you're supposed to put through it.

b) Specified as the optimal current. In THIS case I shouldn't go any higher than 20mA.

superdeformed · Post by **superdeformed** » Sat Feb 04, 2006 12:01 pm

I would guess that it's the current they tested it at for their typical behavioral and optical (ie MCD rating) data. Of course, with only the MCD rating there it really doesn't mean a whole lot. You can probably also take it as the optimal/maximum operating current.

A.J. Franzman · Post by **A.J. Franzman** » Sat Feb 04, 2006 6:03 pm

What he said - it's most likely 1000 mCD at 20mA, and 20 mA is the recommended operating current. You can get more brightness at the expense of greatly reduced life by going slightly higher in current. I would guess an absolute max of 25mA or less. Any more and it could die in minutes or seconds, or get really dim, really fast.