Re: LEDs
- From: "Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@xxxxxxxxxxxxxx>
- Date: Tue, 19 Jul 2005 07:38:42 -0700
<upgrdman@xxxxxxxxxxxxxx> wrote in message
news:1121766553.941190.292190@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> I ended up going with 160 Ohm resistors... 3.2V per LED is what I want
> to aim for... a little brighter, even if it will be a little more
> risky.
>
> i just want to know if its possible to just only current, and not
> influence volatage? From what I read about Ohm's law, I'm guessing No.
> I'm just curious, since I already order'd the resistors I'm going to
> use them, but what if I needed to convserve the most amount of energy.
> Is there any other device that could be used to control the flow of
> power without using it up (ok, lets be real... using less of it up)
....
> more efficient than dissapating it as mostly heat? Something that can
> provide a fixed current and voltage?
Yes, there is, but that is beyond your understanding at this point (see
the following sentence for the reason why).
> Sorry if I sound really new, but I sort of am, and I'm slowly
> understanding Ohm's law.
Since your LED is dropping 3.2V it is likely that it is a white or blue
LED. If so, I have some important info for you.
I have been running some white LEDs at 20mA and 30mA for a number of
months 24hrs, 7days/wk. I have found that there isn't much "risk" in
running LEDs at or above their maximum current. WHat happens is that
the light output drops dramatically after a thousand or more hours.
Some cheaper LEDs running at only 20mA drop to less than a third, more
like 1/10, their light output after less than a thousand hours, which is
only a month and a third, or 42 days.
If you notice, some white LED specs give an "initial" light output which
might be 10,000 mCd. But after a thousand hours, the output might be
closer to 6,000 or 7,000 mCd, so they use the term 'initial' just to be
safe.
> Thanks,
> --Farrell F.
>
.
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