I Know we can't talk about mains transformer less power supply's Big no no. So I'm really not asking about that but I fix a lot of stuff from car heater controls that cost way to much, Flat TV most anything that has a board in it and can be fixed thing's that cost to much i leave alone and replace the bad boards.

Now this is what get's me I've worked on PLC mostly power side of things now some of the boards used optocouplers Lot's did not.

Most anything in the home doesn't I said most anything there are some things the power supply on your computer or a big smp supply some times. The computer supply most do.

These remote Bluetooth and WiFi light's the ones I've took apart don't.

Washer boards nope dryer boards Nope microwave nope refrigerator nope some flat Tv's in the power supply yes some not.
AC units nope.

Now if you add all this up a relay and diode and 2n3904 or a 2n2222 but the 2n3904 is used way more.
I've seen the board on the $1000 vac that runs around your home doing it's job not a one optocoupler

The h bridge plain power npn and pnp transistors.

I Know I have not seen everything made but where are these optocouplers in home home electronics being used.
I've seen a lot of really hurtful looking power supply's no transformer or some that use a 120 volt to 120 volt transformer then head on in to use this to step up and get a little more for CFL lights.

So share were you think all these optocouplers are used.

 

Perhaps they aren't ever used and the manufacturers make several billion of them a year just because it looks good on vendor line cards.

What is your point?

The reason that the owners of the forum have chosen to prohibit discussion of a very few specific direct-to-mains circuits has been explained numerous times. The owners most certainly have NOT prohibited discussion of mains-powered systems.

 

I think I said 2 times mains-powered systems I think the point was clear where are they used I didn't say they wasn't used optocouplers.
I know there used.
sorry about that I left out transformer less which this is not about but.

I said that you'll not find optocouplers much in a home electronics.


But it is about where are all these optocouplers used. And where can you know there used.

The only place I've seen a lot is in industrial controls sys. And like I said your computer at home you'll find one in the power supply.
And some big smp power supply's. The 56 k dial up had one to.

 

I'm not sure what the question is, but I'm pretty sure I don't understand it. If you're asking why more (or all) mains-powered electronics don't have them, it's because the designer decided they weren't the right part for the job. The vast majority of medical, industrial and MIL power supplies have them, and that is a ton of stuff the average electronics person has almost no awareness of. Just one opto anywhere in every car means tens of millions of units per year.

"where are all these optocouplers used" - "these"? Which these? Are you saying that you don't see enough used in enough applications to justify the global annual production rates? I feel the same way about the 555. Over one *billion* per year? Really?

ak

 

But it is about where are all these optocouplers used. And where you know there used.

Looks simple I just pointed out I don't find them much in home electronics.

The vast majority of medical, industrial and MIL power supplies

Now where getting somewhere. That what I ask.

The mains thing was because there are some being used more now but it's with supply's that don't use transformers which we can't talk about here.

Know I'm not saying there is no need for them there really handy but in most stuff at home there not used where it would be a good idea to have used them.
Not seen them in cars but I've not worked on probably where there used.

I fixed a bunch of heat controller boards a few years back the power rails where to small and would burn out if you used low fan speed a lot.

 

Another factor - opto's are less reliable than an additional winding on an already custom designed transformer. The CTR degrades slowly but steadily over time (the first reason I got from one of the big MIL contractors), and by definition two semiconductors are less reliable than a piece of wire (the second reason). Plus you have people like Linear Tech and Power Integrations getting secondary-to-primary feedback through the transformer with no additional winding at all. For low-cost, low power, medium reliability things like home electronics, I suspect this is a real thing. Power Integrations rules these markets.

Another factor - cost. Even at billion-piece quantities, an optocoupler costs more than a penny. For every penny it costs, eliminating it saved 5 billion pennies *per year* back when everything came with a switching wall wart, say 1995-2010. 10 cents equaled 500 million dollars. That's a lot.

ak

 

I used them for high side driver sometimes on h bridge and to save my sound card when I used it as scope.

I've seen them in lots of high output power supply's Just trying to see where people get you need them as much as they do.

Arduino it's optocoupler everywhere but most stuff as I said for home does not use them and works fine.
Don't even start with thing's like small RC cars and even big one's that cost $200 or more there never been much in them.
Cheap low part count.

 

I can speak for HVAC applications. All the logic results (except displays) are used to drive relays, and the relays are a sort of isolating coupler. Most loads are 200 watts to 10,000 watts. An opto would be useless at those power levels and redundant as a form of isolation.

 

Relay's have good isolation too I use them in a lot of lighting.

I just figured I see where people really use these LOL I know how they work I just tend to use what's needed not what's not.

But in the last 17 year's I been inside of a lot of stuff and really I only see opto' s in things you'd find at home. Like You would industrial stuff.

The HVAC stuff is relays delay timers stuff like that.

I remember the older GE zoneline's I bet I replaced controls and bad relays on a 1000 of them I still have some of the relays I got them a 100 at time. Relay was nothing the board was $250 plus.

 

the relays I got them a 100 at time. Relay was nothing the board was $250 plus

That's my favorite part about the fact that you can buy a small microprocessor for about $2. It turns a $30 job into a $300 job.
Now, get off my lawn you whippersnapper!