cheap opamps with offset  like TLE2141 ? - Page 1
Forum section: electronics / general

author: lordvader88
author_rank: Frequent Contributor
timestamp: June 14, 2019, 07:50:25 pm
content: I'm looking for some opamps that can have offset voltages added, like for circuits with relays and hysteresis. The circuit I could make uses TLE2141http://www.ti.com/lit/ds/slos525/slos525.pdfThey're $3.5 each, I'd like to get something cheaper, any idea's ?I order some LM1458 today, I currently have a few other types, for now I guess I have enough GP opamps.

author: exe
author_rank: Unknown
timestamp: June 14, 2019, 09:25:41 pm
content: Virtually any opamp is fine, including lm358, tl072, etc. Seehttp://www.ti.com/lit/ug/tidu020a/tidu020a.pdfor google "opamp comparator hysteresis".

author: lordvader88
author_rank: Frequent Contributor
timestamp: June 16, 2019, 06:11:14 pm
content: So I don't need a special op-amp with offset pins, I can find another circuit for that ok, even better

author: exe
author_rank: Unknown
timestamp: June 16, 2019, 09:24:32 pm
content: These offset pins are not even used...

author: Zero999
author_rank: Super Contributor
timestamp: June 17, 2019, 07:55:40 am
content: The op-amp is being used as a comparator, so the TLE2141 is not the best IC for the job. A comparator IC such as the LM393, LM311 would arguably be better, although the circuit would need to be changed slightly because they have open collector outputs, rather than the push-pull output of an op-amp. An even better option is to use a comparator with a push-pull output such as the LMC6762 or TLC3702.

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 04, 2019, 10:22:40 pm
content: It is being used, the power is on another page.But either way, Ive seen a few circuits using these opamps with an offset, so I was looking for a generic model to buy

author: Dbldutch
author_rank: Regular Contributor
timestamp: May 04, 2022, 08:57:25 am
content: Lordvader88, You use a circuit diagram that was taken from my Blog.It has no indication where you took it from, or who the owner/designer is which is unethical to say the least.Please don't do that and respect the work of others.You don't except PM's which is why I had to do it this way.

author: Zero999
author_rank: Super Contributor
timestamp: May 04, 2022, 09:20:02 am
content: Quote from: Dbldutch on May 04, 2022, 08:57:25 amThe original poster has been banned, as indicated by theemoji.Anyway, he used image tags to insert the schematic, which I don't consider to be unethical because the url reveals where he got it from. I believe there ways to prevent your content being used in this manner if it bothers you.

author: Dbldutch
author_rank: Regular Contributor
timestamp: May 04, 2022, 10:46:02 am
content: Thanks for the quick reply. It does't bother me, since it's an old and no longer relevant circuit, but the source should be mentioned. I don't see the image tags though, just as a matter of interest, how do I get to see them?Thank you!

author: timenutgoblin
author_rank: Regular Contributor
timestamp: May 04, 2022, 10:57:53 am
content: Quote from: Dbldutch on May 04, 2022, 10:46:02 amIs this the correct link?https://www.paulvdiyblogs.net/2017/12/building-curve-tracer.html?m=1

author: Zero999
author_rank: Super Contributor
timestamp: May 04, 2022, 11:09:24 am
content: Quote from: Dbldutch on May 04, 2022, 10:46:02 amClick on the quote button to see the source code used to make the post. I don't know much about website design, but I'm aware of ways to prevent people from accessing files on your server, unless they load the page. It's certainly something to investigate, if it offends you.Regarding the original topic: why use the TLE2141 as a simple comparator? It's a daft idea: way overkill. There are much cheaper, better suited alternatives, such as the LMC7211, which is designed to be used as a comparator. The only reason a sane person would use the TLE2141 is if they have loads in stock and no comparator chips to hand.

author: Simon
author_rank: Unknown
timestamp: May 04, 2022, 12:17:07 pm
content: If you are that bothered put you blog address on the picture.

author: Dbldutch
author_rank: Regular Contributor
timestamp: May 04, 2022, 01:04:42 pm
content: Yes, that is the link, good find. This was a prototype Curve Tracer based on an a very old commercial DIY design. It evolved over a few years into a very good and much more complete design, credit to a small team. Links are in the blog.The reason for the overkill Opamp instead of a comparator is simple. I had a large stash of these Opamps from another project and no comparators at the time. It worked and did the job for that project. The original design of the circuit wasn't really mine as you can see in the blog, but that is beside the point. I made sure credit was published where it was due. As we should always do.I found the url of the original picture. Thanks. Unfortunately it gets to the original location, but doesn't really get you to the Blog post itself.Never mind, I found this circuit and wanted to alert the user. 'Nough said, thanks for chiming in.