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Howto date LEDS

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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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