I was curious, so I looked around. There could be parts that do better but how about 15kV?!
And they will only set you back about $90USD. (datasheet attached)

​

 

A while back in my print shop I was having a huge problem with static discharges false triggering a 555 timer that I ended up building my own opto-isolator using a white LED a length of black acrylic tube and a CDS cell.

I don't know what the isolation voltage was, but it didn't cost me 90 bucks.

 

You can get a Toslink receiver, transmitter and cable for <£10 total. How much isolation would that give?
And it has a response that‘s an order of magnitude quicker than a PC817

 

Both of those solutions will work if you have the room to implement them. Of course you might have trouble getting certifications for them.

On the other hand, using optical fiber for isolation is a standard practice where is works, and it's a good method. I hadn't considered it for a sort of extended opto, rather for a data link, but that could be very useful.

https://www.edn.com/use-plastic-optical-fiber-for-isolation/

 

https://www.digikey.com/en/products/detail/tt-electronics-optek-technology/OPI150/1637927
50k volts for half the price.

 

For plastic fiber we normally use these for isolation and data.
https://www.broadcom.com/products/f...rial/industrial-control-general-purpose/650nm

 

$90 is not such a bad price even figuring in the horrible documentation. (What do those red and white wires do exactly?)

My current employer has one opto isolator, not in the catalog as we can barely make any. When a former customer requested pricing, sales wisely gave them "f you" pricing. They were aghast when the customer accepted. Since there have been several price increases and we're up to something like $800 per device.

Such is business when your part inside a mil qualified device.

(Sorry, no further details will be divulged.)

 

$90 is not such a bad price even figuring in the horrible documentation. (What do those red and white wires do exactly?)

My current employer has one opto isolator, not in the catalog as we can barely make any. When a former customer requested pricing, sales wisely gave them "f you" pricing. They were aghast when the customer accepted. Since there have been several price increases and we're up to something like $800 per device.

Such is business when your part inside a mil qualified device.

(Sorry, no further details will be divulged.)

F you pricing has been a big thing lately. Many companies think they are giving FU pricing but end up getting the project and then get pissed that they didn't ask for more because the upstream components aren't available or aren't available for the price in the quote calculation.

Even a young engineer I know didn't wait for annual March cost of living raises, he just gave an FU "salary increase request" letter to his boss (almost 2x). The boss passed it to the CEO. CEO then stopped by the "kid's" desk to discuss it and agreed to pay him most of what was requested.

Times, they are a changin'.

 

$90 is not such a bad price even figuring in the horrible documentation. (What do those red and white wires do exactly?)

My current employer has one opto isolator, not in the catalog as we can barely make any. When a former customer requested pricing, sales wisely gave them "f you" pricing. They were aghast when the customer accepted. Since there have been several price increases and we're up to something like $800 per device.

Such is business when your part inside a mil qualified device.

(Sorry, no further details will be divulged.)

 

I got to thinking, if I needed to make an optoisolator from parts on hand, could I make something usable?

I thought about an LED and a photodiode or phototransistor (basically, what's inside an opto), and I have some random examples, but I probably don't have two of the same. But I do have plenty of LEDs, so, how about two 3mm blue LEDs?

That blue light does odd things to the camera sensor, and the ends are not shielded.
​

So 8V@100Hz in, 1V out. That could do something useful, and it does provide galvanic isolation. I wouldn't want to guess what voltages I could expect to be safe from. Depending on the application it could be used for something.

​

The waveform starts getting very funky after about 500Hz but I can't tell if the frequency response problem is with the emitter, detector, or both.

 

I got to thinking, if I needed to make an optoisolator from parts on hand, could I make something usable?

I thought about an LED and a photodiode or phototransistor (basically, what's inside an opto), and I have some random examples, but I probably don't have two of the same. But I do have plenty of LEDs, so, how about two 3mm blue LEDs?

View attachment 261248
That blue light does odd things to the camera sensor, and the ends are not shielded.
​

So 8V@100Hz in, 1V out. That could do something useful, and it does provide galvanic isolation. I wouldn't want to guess what voltages I could expect to be safe from. Depending on the application it could be used for something.

View attachment 261249​

The waveform starts getting very funky after about 500Hz but I can't tell if the frequency response problem is with the emitter, detector, or both.

Thanks for repeating a Forrest Mimms experiment from is 1970's and 1980's Electronics Notebook series of books.