Re: Maximum current rating for blue led?


"ehsjr" <ehsjr@xxxxxxxxxxxxxxxx> wrote in message
news:bUjue.13443$tG.11373@xxxxxxxxxxx
> Daniel Morrow wrote:
> > I want to buy some blue leds from digikey (haven't heard back from
them yet
> > about this) and their catalog doesn't list the maximum current
rating for
> > any of the leds they carry, the catalog only lists the maximum
voltage
> > rating. How can I find out the maximum current rating without trial
and
> > error for each individual led and without a risky
potentiometer/multitester
> > method? I need to know the maximum current rating of these blue leds
so I
> > can use the proper resistor with the leds so that the leds do not
get
> > damaged. Thanks a mil!
> >
> >
> Maybe you can help me. I have seen your question, or a variation
> quite often. Personally, I am too chicken to run a LED at or
> near its maximum current, except experimentally. What benefit
> do you see to running a blue LED near its max? Or is it a question
> of finding the max, so that you can run it well below that?
>
> So far (again, aside from experimenting) I have seen no
> advantage to running LEDs "hard" (for lack of a better term).
> I figure 10 mA (or less) as the design figure, unless there
> is a specific reason to go over that. That's not a reccomendation,
> it's just to give you the background behind my question.

> Ed

I came across a receipt from Rat shack back in 2001 when I bought my
first white LEDs. They were four bucks apiece, and I found some others
at a local electronics store for even more. Out of the flashlights I
was building I was trying to get an amount of light that was competitive
with an incandescent lamp, but without spending a fortune. So pushing a
few LEDs, maybe 3 to 6, to their maximum was the only way to go. When I
bought the first hundred Nichias for over $200, I was under a bit less
pressure, but still it's not easy to see most of the cost of a
flashlight tied up in just the white LEDs.

Nwowadays the cost is a dollar each so it's not a ptoblem using twice as
many, but still there's issues of space and complexity.


.

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