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Ldr

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MartyK

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Hi

I'm looking for an LDR optocoupler, ie variable resistance output. So far, the only mfgr I've found is PerkinElmer. Any ideas?

TIA
Marty
 
Many years ago, Raytheon made one, probably not available anymore. You can make your own with an LDR and lamp or LED in a tube (cut a section out of a ball point pen). The lamp will give better control than the LED.
 
They were always a VERY obscure devices - essentially used for audio uses, AGC, guitar effects, things like that - so I would have thought the number of manufacturers was tiny?.

But it's hardly a 'component', it's just an LDR and a bulb (or LED) with a bit of black shrinkwrap around them.
 
Why rip your hair out finding one and just make it. Like Nigel said it's not difficult.
 
MartyK said:
Hi

I'm looking for an LDR optocoupler, ie variable resistance output. So far, the only mfgr I've found is PerkinElmer. Any ideas?

TIA
Marty

If you really want a proper manufacturered LDR, Send me your Name and Address and I'll Mail you one.
 
Clairex (https://www.clairex.com) used to be a biggie in the manufacture of analog optocouplers. I was surprised to find that they had a Web address. I thought that they were the St. Louis based company that was bought out by Perkin-Elmer. Maybe they've split them off again. I dunno. I have a databook in storage somewhere that shows the really nifty product line that Clairex had during the 1980s. As Nigel says, things like that are easy builds for one-of-a-kind projects but would not be practical if you're intending to make 1000 or more of something. The trick is to make sure that your assembly is absolutely light-tight. The teensiest light leak can be detected by an LDR, not really unexpected, considering that their resistance move can often be from under 100 ohms to over 100M ohms.

Dean
 
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