High Efficiency LEDs?

[Shannon H.]

My apologies if the following question is a dumb one, but could someone
please explain to me if there is any difference between the standard
LEDs that one might expect to find at Radio Shack and those installed in
certain newer-model, long-lasting LED-style flashlights, garden lights
and lanterns?

I have seen several products in catalogs in recent months which specify
that because of new technology, their LEDs not only last 1000,000 hours,
but that they draw less power than other, older LEDs. Is that the case?
And if so, could someone tell me specifically where I might be able to
purchase them and exactly what I should ask for?

I'm looking for amber-colored LEDs as opposed to the white ones-- if
that makes any difference. I'm hoping to replace the LEDs in my solar
powered lamp posts which currently yield approximately seven hours of
run time on one day's charge. I'm afraid that switching to another brand
of LED would eat up too much power and make the light last fewer hours
during the night.

Please feel free to email me with any information or advice that you
think may be helpful-- it would be greatly appreciated.

Thank you,

Shannon

 

[Michael A. Covington]

Some LEDs are brighter than others, but Radio Shack generally keeps up with
advancing LED technology fairly well.

The power consumption of an LED depends on its current-limiting resistor.
Swapping LEDs by itself will not change power consumption.

 

[Graham W]

Michael A. Covington wrote:

Some LEDs are brighter than others, but Radio Shack generally keeps
up with advancing LED technology fairly well.

The power consumption of an LED depends on its current-limiting
resistor. Swapping LEDs by itself will not change power consumption.

It will if the Vf (forward voltage) of the LEDs are significantly
different!


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[Watson A.Name - \"Watt Su]

"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:412bf79b$1@mustang.speedfactory.net...

Some LEDs are brighter than others, but Radio Shack generally keeps up
with
advancing LED technology fairly well.

The power consumption of an LED depends on its current-limiting
resistor.
Swapping LEDs by itself will not change power consumption.

Rat Shack may sell LEDs that are bright, but their problem is that they
don't give the customer any specs at all to make a judgment on what's
worth buying. A good example is their white LEDs. They were selling
the relatively wide angle ones for $3 apiece or more a few years ago,
and the only way you could find out that they were wide angle was to buy
one and shine it at a wall or whatever. Nothing on the package to tell
you anything.

In a week or so the LEDs that I've had on a power supply 24/7 since Jul
11 will have two months' of time on them, or about 1500 hours. I've
been running these at 20 mA, and they are doing better than the ones
that I ran at 25mA, which "used up" the Hong Kong LEDs. In another week
or so I'll have to report here on their progress.