General > General Technical Chat
Howto date LEDS
RAPo:
I have a set of (red-) LEDs, no ID numbers.
Is there any way to date these leds?
Gyro:
That's odd (assuming that they're both Red). Early dim Red GaAsP LEDs had a much lower dynamic resistance than modern high brightness types, those started in the '70s though. If comparing the two, I might have put the plots the other way round. The higher voltage one looks very noisy, likely to be defective / reject.
It's hard to tell anything from the plots, you might learn more from looking at the dies.
SiliconWizard:
Dating LEDs from their I-V characteristics is an ... interesting approach.
schmitt trigger:
Perhaps the OP would care to elaborate his theory.
RAPo:
yes indeed, but I double checked the connections/screenshots.
The 19YY LED looks like a desoldered one, maybe that's what we see here.
--- Quote from: Gyro on March 30, 2024, 09:00:50 pm ---That's odd (assuming that they're both Red). Early dim Red GaAsP LEDs had a much lower dynamic resistance than modern high brightness types, those started in the '70s though. If comparing the two, I might have put the plots the other way round. The higher voltage one looks very noisy, likely to be defective / reject.
It's hard to tell anything from the plots, you might learn more from looking at the dies.
--- End quote ---
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