Possible stupid question. Do diodes have a shelf life?

[skiraly017]

I'm sorting through a five pound bag of mixed diodes. Some of them look s little the worse for wear. Can diodes go bad or drift in value due to poor storage? Thanks.

[R.G.]

Yes, they do.

The primary shelf life is for the plating on the leads, which corrodes and gets unsolderable.

Beyond that, the life is limited by the room-temperature rediffusion of the dopants in the silicon (or germanium if that's what they are). This varies with the doping profile, but I was told on good authority that the time to become inoperable is in the thousands of years, not millions of years. If the dinosaurs had figured out how to dope silicon, any that we dug up would be nonfunctional by now.

[skiraly017]

So as long as the leads as good I should be okay. Thanks.

[JimRayden]

So as long as the leads as good I should be okay. Thanks.

Well, for now... better hurry up.

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Jimbo

[Paul Perry (Frostwave)]

Yeah, I've had old Ge diodes where I had to sandpaper the leads before soldering.. OK for one or two, but it gets boring after a few hundred!
Interestingly, I got a bag of  NOS CLM600s that had a pretty high reject rate once. They were very old... I suspect that moisture may have diffused up the leads & damaged the diode or something. I cut one open & salvaged the LDR part, it was perfect as a replacement for an optical wah sensor.