LDR failing

[LaceSensor]

Hi

Is is possible for an LDR performace to change over time? What could cause it to die? Exposure to moisture?
I had to replace an LDR in a tremolo type circuit recently, I removed the existing one and it was reading around 900k in the light!! haha
Put in a new part, and voila, got my trem action back

The surface of the LDR looked a bit "mottled" compared to others in my stocks (I have various types)
I dont know the exact brand or specs of the old broken one as its from a pedal around 15years old

but still, im interested to know if this has happened to anyone else, or what the cause might be?

thanks!

[LaceSensor]

I spoke with Dan Coggins (Lovetone / Dinosaural) and he figures it was likely moisture ingress, and that LDRs can fail by that method.

anyone else?

[Blues Healer]

maybe that's another good reason to use heat shrink!

[midwayfair]

I spoke with Dan Coggins (Lovetone / Dinosaural) and he figures it was likely moisture ingress, and that LDRs can fail by that method.

anyone else?

Cadmium sulfide is not water soluble, so you need to add something else to the mix. http://en.wikipedia.org/wiki/Cadmium_sulfide

I am not a scientist, but this is my guess as to one way this can happen: cadmium sulfide, when exposed to light, water, and air, can produce cadmium sulfate. http://en.wikipedia.org/wiki/Cadmium_sulfate

However, this article suggests that specifically ultraviolet light is the bogey: http://www.rsc.org/chemistryworld/2013/04/cadmium-sulfide-podcast

[LaceSensor]

Fascinating, thanks John

[midwayfair]

Oh, I forgot to mention: some more expensive LDRs are hermetically sealed, which may help keep them going longer.

Also, I nominate "I am not a scientist, so" as the proper reply, perhaps in acronym form, for late night speculative posts about chemical reactions.

[muddyfox]

IANAS sounds great! I vote yay!

[TNblueshawk]

IANAS sounds great! I vote yay!

Sort of rhymes with I anus    But yeah, I second that motion 

[muddyfox]

That's what I always say... A dirty mind is a joy forever! ;-)

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