Electronics > Beginners
Match LED Brightness
tooki:
Well, I just grabbed the electronics catalog that happened to be closest at hand (in this case, Reichelt) and on the first page of LEDs alone, just within the 3mm (T1) LEDs, the light output of the LEDs listed spans 3 mcd to 14,000 mcd at the same current in the same package. Yes, differences in viewing angle account for some of that, but my point remains that "Choosing a similar drive current tells you nothing about whether two different LEDs will have similar light output."
If you're starting by selecting two LEDs with similar rated output at the same current, as you did, then yeah, current tells you something. But if you're looking at LEDs as a whole, it tells you nothing.
Psi:
I remember when i designed some ID badges for a gaming event around 7 years ago.
I did some datasheet research looking at 100's of leds to find the most efficient LED i could.
We wanted the ID badge lighting to last for 3 days straight on two CR2032 but be as bright as possible.
I bought around 30 LEDs from digikey that looked promising and ended one with a InGaN/GaN orange LED that was amazing.
At 1mA it was about the same brightness as most others are at 20mA.
Kasper:
--- Quote from: tooki on November 05, 2019, 10:20:14 am ---If you're starting by selecting two LEDs with similar rated output at the same current, as you did, then yeah, current tells you something.
--- End quote ---
Before accusing me of cherry picking my data, you should look at their site. Relying on such a big assumption just shows you don't have a good argument.
I did not select LEDs with similar rated outputs on purpose. I got LEDs with similar rated outputs because that's what is on their site.
I didn't even limit my selection for package size, viewing angle or cost. I selected the first handful of blues and yellows.
There were a couple with lower intensity but they also had lower current so I did not include them and I was clear about that filtering for 20mA. I almost included them as extra evidence of my argument that lower current generally yields lower output but my post was already too long.
tooki:
--- Quote from: Kasper on November 05, 2019, 04:55:37 pm ---
--- Quote from: tooki on November 05, 2019, 10:20:14 am ---If you're starting by selecting two LEDs with similar rated output at the same current, as you did, then yeah, current tells you something.
--- End quote ---
Before accusing me of cherry picking my data, you should look at their site. Relying on such a big assumption just shows you don't have a good argument.
--- End quote ---
:-DD
Bro, you lost the disagreement long ago. You made a claim that is readily disproven, and multiple people have done just that. You’re just making yourself look silly by digging in your heels on something that is so easily disproven.
Anyhow, I didn’t say you cherry picked your data. You selected LEDs with broadly similar light output. How that came to be is irrelevant. You chose randomly and so did I when I literally grabbed the closest catalog at hand. But the upshot is, your claim that LEDs of similar current will have similar brightness is plain and simply not true.
Zero999:
--- Quote from: Psi on November 05, 2019, 12:04:55 pm ---I remember when i designed some ID badges for a gaming event around 7 years ago.
I did some datasheet research looking at 100's of leds to find the most efficient LED i could.
We wanted the ID badge lighting to last for 3 days straight on two CR2032 but be as bright as possible.
I bought around 30 LEDs from digikey that looked promising and ended one with a InGaN/GaN orange LED that was amazing.
At 1mA it was about the same brightness as most others are at 20mA.
--- End quote ---
It sounds like a phosphor converted LED, similar to the one in the datasheet, I linked previously. Do you have the part number or data sheet?
I found the same yolk yellow LED in TME, for those in Europe who'll find it easier to order it from there, than Rapid. No doubt a similar type of LED can be found in the US.
https://www.tme.eu/gb/details/oscm4l5111a/tht-leds-5mm/optosupply/
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