Hi!
I would like to make a DOD compressor (optical). But I came across the fact that now the use of photoresistors (RoSH) is prohibited in the European Union.
Please tell me how you can replace the photoresistor with a photodiode or phototransistor. I couldn't find anything similar on the internet.
Thank you!
I would like to make a DOD compressor (optical). But I came across the fact that now the use of photoresistors (RoSH) is prohibited in the European Union.
Please tell me how you can replace the photoresistor with a photodiode or phototransistor. I couldn't find anything similar on the internet.
Thank you!
I don't think you can if the LDR is used as a controllable resistor. It might be possible to do something with FETs.
As far as I know, the use of cadmium sulfide LDRs is not forbidden, but selling equipment with such LDRs is, with some exceptions for vehicles, medical equipment and military equipment.
As far as I know, the use of cadmium sulfide LDRs is not forbidden, but selling equipment with such LDRs is, with some exceptions for vehicles, medical equipment and military equipment.
I think it's possible. Not a direct replacement of course. The only embarrassing thing is that I did not find a phototransistor with a dark resistance of about 1mΩ. In the datasheets I can not find graphs of changes in the collector-emitter resistance depending on the illumination. I would like to comply with ROCH. Maybe later I will make another version that can be used for commercial purposes.
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You can try TLX9175J. But I still can't figure out what the resistances are in the open or dark state.
Interesting option. What worries me is the fact that it has a trigger LED current and a return LED current - if that means it has hysteresis, you probably can't use it. Then again, maybe it doesn't.
To confirm what Marcel said, these components are not interchangeable: a LDR is basically a light-controlled resistor, completely linear and symmetrical (in an ideal world, the reality is somewhat less shiny), but a phototransistor or photodiode is mostly is current control device: it is a light-programmable CCS.
In the saturation region, the semiconductors exhibit a LDR-like behaviour, but for a very limited range.
Fets have more symmetry and lineariity, but for a limited range.
There are now light-controlled FET/MOS devices, which should behave more like a LDR, but I have no experience with them, and I cannot tell you how well they perform in real life.
That said, the ban on these devices looks ridiculous considering the amount of active material present in the component: they are practically thin-film devices now, meaning problematic substances are present in the ng range at most.
The currenty available LDRs are ~cheap thin-film types, but they have poor linearity and power-handling. Good, relatively linear LDR's were made in the sixties-seventies by companies of the Philips group: the ORP12 for example.
They used a sintered process instead of a film (thin or thick), and were much better, but they were more expensive and use much larger amounts of theoretically hazardous material.
This has to been seen in perspective: lead batteries are still allowed, yet they contain huge amounts of lead.... go figure: ng against kg
In the saturation region, the semiconductors exhibit a LDR-like behaviour, but for a very limited range.
Fets have more symmetry and lineariity, but for a limited range.
There are now light-controlled FET/MOS devices, which should behave more like a LDR, but I have no experience with them, and I cannot tell you how well they perform in real life.
That said, the ban on these devices looks ridiculous considering the amount of active material present in the component: they are practically thin-film devices now, meaning problematic substances are present in the ng range at most.
The currenty available LDRs are ~cheap thin-film types, but they have poor linearity and power-handling. Good, relatively linear LDR's were made in the sixties-seventies by companies of the Philips group: the ORP12 for example.
They used a sintered process instead of a film (thin or thick), and were much better, but they were more expensive and use much larger amounts of theoretically hazardous material.
This has to been seen in perspective: lead batteries are still allowed, yet they contain huge amounts of lead.... go figure: ng against kg
Thank you!
This is just an approximation that such use is possible.
That's why I asked the question. Perhaps someone knows the correct option.
This is just an approximation that such use is possible.
That's why I asked the question. Perhaps someone knows the correct option.
If you need a photoresistor, I have at least tens of them in my stock, if not hundreds. If you need one I can send you one ( or half a dozen) for free. Just PM me with your exact requirements, and I might have something suitable
This is a radical departure from the simple concept of directly using an LDR as part of a voltage divider for volume control, but it occurs to me you could use the output of a photodiode driven by an LED to modulate the tail current of a diff pair, and hence its gain. An old dinosaur IC like the RCA/Intersil CA3080 might also be useful in this respect.
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True, but he´s trying to clone a specific DOD pedal. which happens to use LED/LDR attenuator in the NFB path.
LDR is floating so no "shunt to ground" approach woks.
But thanks God kind Elvee saved the day 🙂
LDR is floating so no "shunt to ground" approach woks.
But thanks God kind Elvee saved the day 🙂
Thank you! I read about it.
Thank you so much! I live in Bulgaria. Photoresistors are still available in the store. So I can make a device for myself. But I would like to try to make this device so that it could be sold. And in this case, it makes sense to look for other replacement options.
Most likely it won't fit. But the idea is interesting. I'll think about it.
If you want to make a prototype pedal, build it with the LDR generously offered by Elvee.
If you want to build a few, and try to sell them at a Boutique/Home level, go and grab what´s available locally.
IF it becomes a resounding success and tens or hundreds are needed (hey! ... why not?), then the kind Alibaba guys will supply you as many as you want.
Personally I fully agree with keeping contamination out of land and water, but Politicians as usual have no clue and don´t care, and contradict themselves in a GROSS way.
As in: lead is bad, sure, lead in solder IS a factor ... but they exempted CAR INDUSTRY 😱 from that (obviously for $$$$$$$ reasons) .... so they forbid a couple Tons and allow THOUSANDS??? WTF???
By the same token, Cadmium was once popular for chassis plating (I still remember 70´s and 80´s typical Japanese multi-hued yellowish chassis) which admittedly aggregated up to Tons into dumpsters .... but a CDS cell uses an atoms thin layer covering a 5 mm disk, a few MICRO grams at most .... many orders of magnitude difference.
Oh well.
If you want to build a few, and try to sell them at a Boutique/Home level, go and grab what´s available locally.
IF it becomes a resounding success and tens or hundreds are needed (hey! ... why not?), then the kind Alibaba guys will supply you as many as you want.
Personally I fully agree with keeping contamination out of land and water, but Politicians as usual have no clue and don´t care, and contradict themselves in a GROSS way.
As in: lead is bad, sure, lead in solder IS a factor ... but they exempted CAR INDUSTRY 😱 from that (obviously for $$$$$$$ reasons) .... so they forbid a couple Tons and allow THOUSANDS??? WTF???
By the same token, Cadmium was once popular for chassis plating (I still remember 70´s and 80´s typical Japanese multi-hued yellowish chassis) which admittedly aggregated up to Tons into dumpsters .... but a CDS cell uses an atoms thin layer covering a 5 mm disk, a few MICRO grams at most .... many orders of magnitude difference.
Oh well.