How an Optocoupler Works, and How to Use Them -- DC to Daylight 17

I don't know why semiconductor manufacturers haven't put more effort into containing magic smoke - this is a problem that continues to plague us all. Until they come up with a robust solution, we'll just have to keep on using optocouplers, and our bill of materials will just have to take the hit.

Thanks!

Derek

I started using Opt-couplers why back maybe 3 decades ago? (hp stuff) they are really nice for HV isolation LOL to me anything over  5v is HV. I currently use them in some of my displays that take 28, and 12 volts, OUCH, this will turn your microprocessor into a brick, and all the magic will come out very suddenly.

• Smokeless CPUs: Smokeless CPUs are incompatible with the Linux kernel and it is doubted that any work will ever be performed to change this. They are simply too unreliable in even the most standard system configuration. Those with a CPU missing its Magic Smoke should switch to a new CPU.
• And BTW toss the board as well - CAH

They're handy devices, especially for logic level translation - as long as the frequency isn't too high. Good luck, and drop back in if you need to bounce a schematic off me (or anyone else here).

Interesting. I wonder what their purpose was... maybe in some kind of compressor circuit to prevent overdriving an audio stage, or maybe to limit the current going to the write head of a tape? Bakelite definitely dates it to that era - I had an old bakelite Simpson voltmeter, that I unfortunately had to retire, being dropped too many times. Fragile stuff that bakelite.

Hey Doug. Sorry for the late reply!

You've got a lot of great content out there. I especially like the quadrature circuit you put together. Every now and then I travel around and have to give a training session on robotics basics, which includes quadrature signals. I may have to build up a circuit like this so folks can enjoy seeing what is actually going on with the motor feedback. (I usually just put up a couple of slides) Awesome stuff!

Nice post.

I have not used optocouplers, but I have seen them in use on a lot of circuits.

When I get some time I may have to play with them.

I can recall from teardowns of 1950s/60s office dictation equipment, finding LDRs close-coupled with incandescent torch bulbs. They were contained in a light-tight Bakelite housing that was held together with a spring clip allowing you to replace the light bulb.

Presumably a predecessor to the Vactrol device?

I used optocouplers in a few projects on element14:

/challenges-projects/project14/provingscience/b/blog/posts/electric-hula-hoop

/challenges-projects/project14/digitalfever/b/blog/posts/the-logical-project

/challenges-projects/design-challenges/pi-fest/b/blog/posts/it-came-from-the-synth---mystery-melody-medley-5

Hey there! Have a unique application using optocouplers? DIY coupler, audio compressor, guitar effect or maybe an encoder? I'd like to see what you've put together - drop some photos here so we can check it out! -Derek