2mV opamp

found in discarded consumer appliances. I'm well rusted re what offerings t here are out there now - any suggestions? Sadly the 324 & 358 arent low off set enough, 061/071/081 are much higher offset, and 741/4558 are no good ei ther.

My understanding is that even with the old part numbers the new processes m ake the performance much better. The challenge might be to find one with of fset that bad. Then there is the fallback of current source (large adjustab le resistor) injection into an input nulling node.

Common as water.

It's pretty easy to do a parametric search on opamps but 2mV is a ten cent class opamp these days. Forty plus years ago, as the part numbers you quote, not so much.

LM833 but it would be better to design to use 'generic'

found in discarded consumer appliances. I'm well rusted re what offerings t here are out there now - any suggestions? Sadly the 324 & 358 arent low off set enough, 061/071/081 are much higher offset, and 741/4558 are no good ei ther.

Any trimmable op amp will do, 741 is fine. Just tap a key that connects a headphone across the input terminals, and adjust to minimize the click you hear. It takes a trimmer pot, though.

I'm not sure how many single op amps with trim pins ARE to be found in post

-consumer electronics... but old TVs had lots of trimpots.

, found in discarded consumer appliances. I'm well rusted re what offerings there are out there now - any suggestions? Sadly the 324 & 358 arent low o ffset enough, 061/071/081 are much higher offset, and 741/4558 are no good either.

a headphone

It takes a trimmer

st-consumer

There is that option... but it would require headphones and a preset pot pe r amp, not ideal. And old preset pots arent too reliable. I'd rather just s ay these parts will work off the bat.

NT

Then why does he even need to ask?

And why has there not been an answer yet?

The "found in discarded consumer appliances" is the issue. Who's going to know that? What consumer appliances need low-offset opamps?

Many parts in consumer gear are house-branded anyhow.

found in discarded consumer appliances. I'm well rusted re what offerings t here are out there now - any suggestions? Sadly the 324 & 358 arent low off set enough, 061/071/081 are much higher offset, and 741/4558 are no good ei ther.

PMI were the first to introduce a trimmed low off-set integrated circuit op erational amplifier - the OP-07 - and everybody else second sourced it with a few years.

I don't think that you'll find many in discarded consumer appliances, but q uite a few were sold.

I check out scrap items so I'm upto speed on what's available to work with. There are lots of familiarly marked opamps, as well as unfamiliar markings. Mainly its LM358 & 324. There are many IC numbers I dont see often enough to bother looking up too.

NT

Ask him.

Because there are simply too many to list. Look them up yourself if you're that interested. It really isn't hard to do a parametric search (or sort) on any of the supplier's sites. On ADI's site, at least 3/4 of the opamps fit the bill. ...probably 7/8 on TI's.

question was which are common in appliances

I did that searching and got nowhere. Sites that listed V offset had wrong data, eg 324 & 358 listed as meeting the 2mV spec, which they dont even come close to. Plus none of those sites give much data on which are most common.

But its now solved, and I've been reminded how rusty I am! Thanks to everyone.

NT

, found in discarded consumer appliances. I'm well rusted re what offerings there are out there now - any suggestions? Sadly the 324 & 358 arent low o ffset enough, 061/071/081 are much higher offset, and 741/4558 are no good either.

operational amplifier - the OP-07 - and everybody else second sourced it wi th a few years.

quite a few were sold.

thanks, that could prove useful.

NT

The hard bit is knowing if any are "found in discarded consumer appliances". Only thing I can think of is the OP07 that Bill mentioned, but that is a long shot too probably. Might get used for a thermocouple circuit, boiler controller? Anything else?

Maybe some load cell-based scales. Thermocouples are quite rare in consumer goods.

Funny claim sine my most recent motherboard has several on it. Even CPUs are incorporating them now.

Plenty on my older PC machines too. Cheap meter from Harbor Freight... comes with one. They also have cheap IR instruments.

^^^^

Lay out any interesting PCBs lately?

I'd very expect that to be diodes and not thermocouples

-Lasse