Talk:Operational amplifier

Hyphens

The hyphen usage on this page is incorrect. Putting a hyphen between two words creates a compound adjective. Thus, "operational amplifier" is a noun, but "operational-amplifier" is an adjective. Likewise in the abbreviation, "op amp" is a noun, and "op-amp" is an adjective. For example, "This high-speed op amp doesn't work in this op-amp circuit." I know that there are many "common" examples of incorrect usage, but ask an English teacher: "op-amp" is not a noun. (Also, "opamp" is an abomination.) — Preceding unsigned comment added by 24.147.65.117 (talk) 00:07, 11 July 2012 (UTC)

I agree. At some stage I'll go about removing the hyphens if no one else objects?Accidentprone104 (talk) 17:43, 11 December 2012 (UTC)

I have removed unnecessary hyphens. ~Kvng (talk) 15:41, 11 July 2020 (UTC)

Seperate page for the μA741?

The μA741 seems important enough in it's own right to have a separate page. I nominate a potential split from Internal circuitry of 741-type op-amp into a new article. The Manic Puppeteer (talk) 15:51, 28 July 2015 (UTC)

Seems like a good idea and the basic WP:N stuff is well surpassed by the huge sourcing for both aspects.

Couple of questions though:

• Split or duplicate? We can choose to do either (see below).
• Is the internal structure of the 741 relevant to an op-amp article that it primarily about the use of op-amps as building blocks, secondarily (and very importantly) as explaining the internal structure of an op-amp? This is "op-amp", and not "history of op-amps". The history is important, but it's a big enough overall topic, and there's a big enough need for a "current status only" article that too much history shouldn't be in this top level article. So, ignoring the later developments like high impedance inputs, is the 741 circuit still relevant as a block-structure level explanation of op-amp internals? If it is, we keep it in here (i.e. duplicative overlap rather than simple split). If it's an evolutionary dead-end or misleading per contemporary practice, we remove it through a straightforward split. Of course both copies, here and at 741, may then develop either broadly or more narrowly.
• Is the internal structure of the 741 specific and novel to the 741? (dim memory suggests it is) Or is it merely a development of the 702? (709 / 101 or whatever). If it's novel to the 741, then it belongs in a 741 article. If it's just gradual evolution, then maybe the split should be Operational amplifier and History of operational amplifiers / History of integrated circuit operational amplifiers, rather than prioritising the 741 uniquely. There are whole books on op-amps, so even having two history articles would be permissible. You could certainly write them as two, then merge later. Andy Dingley (talk) 16:09, 28 July 2015 (UTC)

I believe that the 741 has a unique internal structure, though it was technically a development of the 702, it diverged far enough from the original design to merit a separate article. I'm also taking into consideration the fact that the 741 is the effective "555 of op-amps" owing to it's ease of use, relative stability, reliable performance, and wide prevalence. I also believe that the 741 is still relevant to op-amp construction, as it's architecture is somewhat of a standard even in contemporary op-amps, so perhaps a duplicate would be better. The Manic Puppeteer (talk) 18:59, 28 July 2015 (UTC)

In which case, copy a bunch of content from here into a new article on the 741, trim down anything here that isn't generic or a precis of the 741 and then let the two articles grow independently. Andy Dingley (talk) 19:17, 28 July 2015 (UTC)

• Not sure, leaning oppose. The μA741 was a dominant op amp, but I'm not sure there's a whole lot to say about it in an encyclopedia. IIRC, the history is Robert Noyce let Bob Widlar experiment with analog circuits. Widlar used RTL as an amplifier. Then he made the μA702 using a vacuum tube level shifting circuit. Then there was the μA709 (and the side branch instrumentation amplifier μA725). The 709 set the basic pattern of diff amp, CE gain, and push-pull output. I think the 709 was the significant op amp, but the frequency comp issues were a little daunting. The following designs refined the stages (e.g., lower bias currents; short-circuit protection), made better use of the crummy PNPs, and improved the process. LM301. The 741 used internal compensation, so it was the user-friendly opamp. The better article would be one about the evolution of the opamp's internal circuitry. I think Solomon wrote about that. Glrx (talk) 19:13, 30 July 2015 (UTC)

I aggree that there will not be a long article on the 741 alone. But does that matter - short articles are not bad. It's more the 500+ lines articles that are a problem. The internal circuit is not that unique - the lm101 is rather similar, except for internal compensation. So one could handle both OPs in a single article. The 741 internals are also different from many modern OPs - so having the detailed describtion of the old circuit may be a little misplaced in the general OP article.--Ulrich67 (talk) 18:44, 8 November 2015 (UTC)

- As an alternate point of view, this "internals" section you propose to move was _exactly_ what I was looking for when I came to this page. TdewolfWiki (talk) 05:27, 23 September 2016 (UTC)

This discussion is nearly two years old so I am being WP:BOLD and removing the tag from the main page. Martin of Sheffield (talk) 13:03, 6 April 2017 (UTC)

• Support The 741 definitely qualifies for a separate article but that doesn't mean it needs to have a separate article. 741 theory of operation is instructive to understanding the internals of an op amp but it would be just as effective in this role as a link to a stand-alone article. Having this material inline in this article takes readers into the weeds and we don't want to do that so I support splitting this into a stand-alone article. ~Kvng (talk) 15:50, 11 July 2020 (UTC)

Will be calling this article to the attention of various admins

…as a near to completely plagiarised, blatantly academically dishonest presentation of electronics/electrical engineering content. This is no common knowledge material. Whatever the history of the article, current editors need to review WP:VERIFY and WP:OR, and stop rationalizing that the article is fine. Section after section, paragraph after paragraph of material taken from external sources unnamed is plagiarism and violates WP:VER. Expert content written by WP editors from their personal knowledge base that cites no sources to allow verification violates both WP:VER and WP:OR. There is no excuse for this (especially not that it has always been this way, or that many articles are likewise in violation). I will call attention to this in whatever ways I can, to make clear the hypocrisy of longstanding, basic science and technology articles, whose material is unsourced, and therefore non-encyclopedic and dishonest. Le Prof 73.211.138.148 (talk) 00:28, 2 December 2016 (UTC)

What sources were used? What sources do you suspect were used? --Mr. Vernon (talk) 00:35, 2 December 2016 (UTC)

That is the very point—we do not know, despite this being required by WP:VER. Hence, it is either plagiarised, or original research, both of which are prohibited. See next example. Leprof 7272 (talk) 00:38, 2 December 2016 (UTC)

An example, because an editor has come on, indicate light sourcing, but no issue. In the first major section, tens of lines long, where appears the following equation:

$V_{\text{out}}=V_{\text{in}}+i\times R_{f}=V_{\text{in}}+\left({\frac {V_{\text{in}}}{R_{g}}}\times R_{f}\right)=V_{\text{in}}+{\frac {V_{\text{in}}\times R_{f}}{R_{g}}}=V_{\text{in}}\left(1+{\frac {R_{f}}{R_{g}}}\right)$

there is but a single citation, and it only appears in the third subsection, leaving the first two subsections of the first section completely unsourced, and this particular non-common knowledge violation of WP:OR and WP:VER unsourced as well. Moreover, this section represents the rule—sections with block after block of unsourced material—and not an exception. Leprof 7272 (talk) 00:38, 2 December 2016 (UTC)

If you believe this to be a violation of copyrighted materials, by all means bring it to WP:CP. --Mr. Vernon (talk) 00:42, 2 December 2016 (UTC)

Even if public domain material was used, it is nevertheless plagiarised until that public domain source is named. The sloppiness reflected in cribbing material from sources without attribution makes it reasonable to assume that the same sloppiness might have been applied, both to public domain information, and to copyrighted sources. The tag should remain until it is determined where the bulk of material was drawn, and that source is named. Leprof 7272 (talk) 00:46, 2 December 2016 (UTC)

I'm not doubting you. There are admins and editors on WP:CP who are bloodhounds at sniffing out the source of copyrighted content. It should be removed and it would be very helpful if you would report it. As an editor who recently spent a significant amount of time tagging obvious copyvios for speedy delete, I would certainly appreciate it. --Mr. Vernon (talk) 00:50, 2 December 2016 (UTC)

There is a big difference between "unsourced" and OR. OR would mean an editor made up the equations, and the circuits, shown here. However, almost everything in this article was commonly covered in undergraduate courses in EE since at least the early 1970s. Every calculation shown here has been done thousands, if not millions, of times by students in the last half century. So almost all the statements here are not OR that should be removed - they are correct statements representing common knowledge in the field. Furthermore they *are* referenced - the sources in "For further reading" and "External links" include all the information given in the article, plus a lot more, including many reliable sources in the technical literature.

As far as copyright violation, as an experiment I took three phrases from the section you mention. I looked in Google scholar, Google books, and the usual google search. In previous cases I have investigated, this almost always found the original source. Here, one of the phrases was indeed found in other sources, but all of them I could find were later than the introduction of the text into Wikipedia. Hence they were likely copied from Wikipedia, and not vice versa.

Overall, citations per paragraph would be nice, but this a mechanical exercise given the references already provided. And of course copyrighted text should be removed, if it is found in the article. But this situation is not as dire as you portray. LouScheffer (talk) 05:18, 2 December 2016 (UTC)

To the OP: article talk pages should be used for actionable proposals. There is nothing to substantiate a need for copyvio or too-technical tags. Please post a reason why these tags should be retained. People with an understanding of the topic can see that it is just a bunch or routine statements in accord with hundreds of basic text books. Yes, more sources would be good, but there is no reason to think WP:OR is involved. Per LouScheffer's analysis and past experience, it is very unlikely that anything in the article is a copyvio. Johnuniq (talk) 06:17, 2 December 2016 (UTC)

Not OR, and not COPYVIO either. These derivations and formulas are part of the common knowledge and appear in one form or other in every book on the topic. One might as well claim that any rendition of Ohm's Law or Maxwell's equations must also be a COPYVIO. Heck, the derivation quoted above is Ohm's Law, restated with the symbols used in that context. Jeh (talk) 09:06, 2 December 2016 (UTC)

Yes. Many things are commonly known, and so not WP:OR, though someone can always question it. Most things from undergraduate texts are commonly known and don't need a reference, though sometimes it is nice to have one, anyway. Gah4 (talk) 00:10, 17 January 2021 (UTC)

nb1

Regarding nb1 and the definition of zero. Because of the high open-loop gain, it doesn't matter so much the exact meaning of zero. In most cases, it is only in a completed circuit where the definition matters. Otherwise, for ones that do have the offset leads, you build the circuit and then adjust for the appropriate zero, which might include some other offsets, too. Gah4 (talk) 00:20, 17 January 2021 (UTC)

Timeline - FET OPs

In the timeline the point under 1970s about FET OPs is a bit confusing and vague. The early FET OPs were JFET based as hybrids - so seprate chips for the JFETs at the input and the main part. Later came JFET based monolytic OPs and also CMOS based monolytic OPs. CMOS OPs got a lot more popular, espeically for low votlage use, but have not fully replaced monolytic JFET input OPs - only for a few super low bias applications. Relevant milestones may be the first monolytic JFET input OP and CMOS OP - could be problematic if the early ones were rare, special ones. --Ulrich67 (talk) 18:02, 3 February 2021 (UTC)

First produced

The first produced year seems to be for the 741, but that wasn't the first opamp. The uA702 was released in 1963, which was probably the first monolithic opamp. But there were opamps before that. 72.74.174.182 (talk) 03:48, 5 January 2023 (UTC)

"First produced"

The article currently has "First produced" in the infobox set to 1967, which seems odd to me, as this year is not the date of the first op amp, first commercial op amp, first IC op amp, or the op amp pictured directly above. I am not sure which of these things "First produced" is supposed to refer to, but in any event the date seems wrong? Craig Stuntz (talk) 17:18, 29 March 2023 (UTC)