Why are optocouplers so expensive??

[Connoisseur of Distortion]

it's so simple: a LED and a LDR in the same enclosure. why do they cost so much?

any insight would be killer.

[Tim Escobedo]

Low demand.

[Gladmarr]

This one isn't too expensive  http://www.goldmine-elec-products.com/prodinfo.asp?number=G15396

[Connoisseur of Distortion]

Gladmarr- i noticed that one. haven't tried them yet, but intend to.

Tim- i figured that they have decent demand, because they are used in audio applications including amp channel switching (which usually takes a good number of them). are they used outside of audio at all??

[Dingleberry Electronics]

NSL-32 from Silonex isn't so expensive. Works wery well in audio applications.
http://fi.farnell.com/jsp/endecaSearch/searchPage2.jsp?specialorder=on&Ntt=nsl-32&Nty=1&N=0&Ntk=gensearch

I think that normal LDR's vary more with their resistive tolerances than opto's. Think that optos should behave more in the way, what's written on the spec sheet. If you check a hanful of cheap LDR's with your DMM you might notice that they all ain't what they supposed to be. So I think it's just the matching process what makes them cost a little more than led and LDR.   

[Mark Hammer]

This one isn't too expensive  http://www.goldmine-elec-products.com/prodinfo.asp?number=G15396

That would appear to be an unmarked Clairex.  My guess is that it is off spec in some manner.  Peter Snow was good enough to give me a couple similar units he had bought cheap last year.  I haven't built anything with them yet, but testing them shows a nice range of resistance variation and a strong likelihood of them being very usable....as long as there is no great need for matching them.

So, using them for a noise gate, a compressor, or any autowah where the filter does not depend on two resistances changing equivalently (e.g., Mutron, Meatball) looks like a thumbs up to me.  You may have to tinker with series and/or parallel resistances to get it to work "just right" but that's trivial.  The price is right.

[RedHouse]

I have some of those, they are marked "NSL 7053", they are recognised by Silonex as the NSL marking would imply.
(I emailed Silonex about 'em)

They contain a failry fast acting LDR that goes from over 10m (dark) to less than 1k (light).

They are encased in plastic which I successfully opened by rolling a Xacto blade around the side cuting them in half, the LDR is usable separatly after the diode half is removed.
(used them in a bulb-driven univibe clone)

[Sir H C]

Unique packaging is a big thing.  You go to get them made up, it requires special equipment that is not there for every other IC put together.  Keeping that equipment where you could be using it for other higher volume things, is an expense that these guys want to be recouped for.  Also how many do you concider "a lot".  If you make fewer than a million, and you are a billion dollar company, why bother unless you roll them up with other parts you make.  Most companies couldn't be bothered unless they feel they can make a million a year off of something.

[RedHouse]

Sorry for the typo,  should have read "they are NOT recognised by Silonex..."