SBG-PID

[6666]

Just to get the circuit working try using a pin compatible op amp

[ionut_mtb]

If you want to play safe; this is the only way:

https://octopart.com/lf357h-national...SAAEgKxdfD_BwE

this is a search engine for electronic components, this does not means that supplyers can be trusted..

[Carl-NC]

Which?
And then does the wiring have to be changed?

Figure out which specs matter. In this case, GBW certainly and probably IBias. Maybe more. Then use a search engine to find other opamps. I personally like Digi-key's search, you can easily filter on various specs.

[dbanner]

I use NE5534 to replace lf357 on another project some time aback, pin 1,8 balance/compensation. get rid of coupling cap on input. etc.etc. Worked excellently. Obviously requiring bodge work on pcb.
Direct replacements for lf357n are for fishing expidition of Dr. Livingstone. However I have said it before and I'll say again, buy genuine NTE replacement for LF357N. It performs exactly like original. It is NTE937M. Order it directly from NTE electronics. I used one and it works a treat.

[sinclairuser]

hi, we always get the inevitable questions "can i swap this chip with that chip?", "can this transistor be used instead of that mosfet?".
etc etc my own view is that it is better to use the correct components even if they cost a bit more, having said that some builders seem to have real problems getting the right parts, and through no fault of their own too.

some of the older projects have parts that are considered obsolete like the lf357n though dbanner has given you an excellent viable alternative, sometimes parts can be substituted with careful datasheet checks, but others while alternative parts will work they wont work right, sometimes its due to a particular feature or even a quirk or bug in the component that the original designer exploited, in a case like that its very difficult to replicate with a modern alternative.

luckily the newer projects are mostly designed with common parts so having to source "wildcard" components is not a problem, though you still get those who try to make apple pie with pears and tomatoes.
thanks,
aly.

[scs]

Leave the soldering iron. The beach is more pleasant.

[Andi68]

The NTE 937M is no alternative, it is even harder to obtain in Europe than the LF357.
Well, I'll see which operational amplifier is suitable as a replacement.
It takes time and my motivation to finish the circuit quickly is not great
For me it's the last circuit with obsolete semiconductors that I build.

[6666]

[ATTACH]46787[/ATTACH]Leave the soldering iron. The beach is more pleasant.

That beach even has a McDonalds

[dbanner]

A look at the respective data sheets of the NTE937M and the LF357N show exactly the same AC electrical characteristics. The NTE937M is a direct replacement for the LF357N. The other characteristics such as max. supply voltage, diff. input voltage, input voltage range etc. are not an issue, since they are well within the operating criteria for this circuit.
Another thing is that there are no fake NTE chips when ordered from NTE supplier/agent/vendor.
I only offer one suggestion, as I am sure there are other chips which could do the job.

[dbanner]

[ATTACH]46787[/ATTACH]Leave the soldering iron. The beach is more pleasant.

Why don't you post a video demonstration of your working unit? A bench test for example.
It would be nice to see performance of original working prototype for comparison of results of subsequent builds.

[Andi68]

LF157, LF257, TLE2081, CA3130?

[Andi68]

I am in the process of preparing the components.
As many used parts of the scrap as possible should be used.
This takes a little more time than ordering new ones
I mean, it's tight on the board.

[dbanner]

I am in the process of preparing the components.
As many used parts of the scrap as possible should be used.
This takes a little more time than ordering new ones
I mean, it's tight on the board.

Take your time, and good luck to you. I'm surprised nobody can yet produce a working device after so long.
I'm not in the mood for hobby building these days. I'm feeling uninspired to build yet another pulse machine.

[Andi68]

Thanks dbanner.
In the mood I'm not right ....
I think few are motivated to build the circuit because there is no proof that it works.
Sometimes I think I give up the project myself.

[6666]

Thanks dbanner.
In the mood I'm not right ....
I think few are motivated to build the circuit because there is no proof that it works.
Sometimes I think I give up the project myself.

I have started but got a few other things to do