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This is an old revision of this page, as edited by 86.162.147.159 (talk) at 17:18, 10 October 2022 (→Disputed section on audion). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Untitled

I'm a little worried this article has become overmerged. There was once receiver (electronics) which made sense for some applications; there should also be receiver (telecommunications). Both are different than the receiver appliances that are discussed in this topic. -- Mikeblas 20:16, 27 January 2006 (UTC)[reply]

I would agree, in that a discussion of what we used to call a "Hi-Fi Receiver" (integrated receiver) has seemed to overwrite the basic "radio" receiver
a break out of
  • Receiver (radio)
  • Receiver (High Fidelity) or (audio)
  • Receiver (communications)
would not IMHO be out of line, with links to each other of course. cmacd 14:55, 8 September 2006 (UTC)[reply]

I've removed some interesting text from this article about the history of radio. While unreferenced, it was pretty welll-written. I think it would be far more appropriate at the Radio article, which has a "History" section. -- Mikeblas 19:06, 10 October 2006 (UTC)[reply]

Contradiction

Receiver (radio) "The first integrated stereo receiver was made by the Harman Kardon company, and came onto the market in 1958. It had undistingushed (sic) performance..."

Harman Kardon "One year after its founding, harman/kardon introduced the world's first true high-fidelity receiver, the Festival D1000. This monaural unit was not only aimed at non-technical consumers but also incorporated many now-familiar features such as the incorporation of a tuner, component control unit and amplifier on a single chassis."

I find on one hand ascribing "undistinguished performance" to the Festival D1000 in Receiver (radio), and then at Harmon Kardon labeling the Festival D1000 to be a "high-fidelity receiver" to be contradictory. - MSTCrow 03:14, 3 December 2006 (UTC)[reply]

History section

Added a needed history section focused specifically on the development of the radio receiver, based on a comprehensive overview document source. Will find more variety of sources to add. - LuckyLouie 19:10, 11 November 2007 (UTC)[reply]

Russian inventions category

Since the first radio reciver was invented by a Russian, Popov, it's category is Russian inventions, just like Tank is in British inventions, since the first to built it was British, and thats why it's categorised in British inventions. Shpakovich (talk) 21:54, 7 May 2008 (UTC)[reply]


Inputs

All other common audio/visual components can use any of the identical line-level inputs on the receiver for playback, regardless of how they are marked (the "name" on each input is mostly for the convenience of the user.) For instance, a second CD player can be plugged into an "Aux" input, and will work the same as it will in the "CD" input jacks

... except mic inputs, which are found on some home stereos Tabby (talk) 07:56, 14 May 2008 (UTC)[reply]

And except for phono inputs designed for magnetic phono cartridges. Ceramic cartridges might be line level. Gah4 (talk) 02:02, 23 May 2019 (UTC)[reply]

1930s radios

"by the mid 1930s virtually all receiving sets in Europe as well were using the superhet principle"

this is simply not the case. There are a number of standard radio configurations seen in the 30s as technology progressed, but only a small minority were superhets, which were at the time simply unaffordable to the great majority of buyers. A trip to any suitable museum will show you what was in general use at the time.

Superhets established dominance by the 50s. Tabby (talk) 07:56, 14 May 2008 (UTC)[reply]

Seems to me that use and for sale should be separated. As well as I know, by the early 1930's the ones for sale would be superhet, as they are enough easier to make. It would be some years before those replaced existing sets. Gah4 (talk) 02:04, 23 May 2019 (UTC)[reply]

RF probe

I think that the article RF probe should be merged into this article as it is too short and not important enough to have it's own article page. OpinionPerson (talk) 21:25, 12 June 2008 (UTC)[reply]

The RF probe is mostly a measuring instrument interface. It does not fit well here. Sv1xv (talk) 13:45, 26 August 2008 (UTC)[reply]
I agree. Removing tag. - LuckyLouie (talk) 20:55, 11 December 2008 (UTC)[reply]

Possible Edits

1. Elaborate more on the specifics of how it works. 2. I personally feel that we should erase the Manufacturers section. It's just free advertising for Panasonic, Aiwa, and whatever. Worst of all it's like the only manufacturers in the world are Panasonic, Aiwa, etc.

Exec. Tassadar (comments, contribs) 12:46, 24 August 2008 (UTC)[reply]

I agree about the manufacturers; there are too many to mention. ·:· Will Beback ·:· 16:47, 24 August 2008 (UTC)[reply]
Agree about mfg.s also... - LuckyLouie (talk) 13:26, 26 August 2008 (UTC)[reply]

The new article name is not much better

Recently the page was moved from Receiver (radio) to Radio (receiver) [1]. I understand the motivation, as the name Receiver means a lot of other things, but I don't think the new name is much better. "Radio" is insufficiently specific as it also refers to two-way radios like CB radios and walkie-talkies. It also is easily confused with the article Radio, referring to radio technology in general. I think Radio receiver would be better. This satisifies WP:COMMONNAME: "...the name that is most commonly used as determined by its prevalence in reliable English-language sources", reliable sources in this case being the electrical engineering and telecommunications fields. Radio (receiver) can be a redirect. --ChetvornoTALK 20:58, 28 October 2015 (UTC)[reply]

Yes. I confess to failing to find the discussion or even proposal of the move as suggested in WP:MOVE. What merits were argued, for retaining the (quite unnecessary) parentheses? Anyway, yes, Radio receiver is also my preference. Jim.henderson (talk) 13:21, 30 October 2015 (UTC)[reply]
Agree, this should probably have been reverted and discussed, but Chetvorno's proposal of Radio receiver looks good. Fountains of Bryn Mawr (talk) 13:27, 30 October 2015 (UTC)[reply]

Requested move 30 October 2015

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: moved. The redirect at the target had previously been a stub but had no significant content or history. None of the text from that stub appears to have made its way to the article being moved over it, nor would it add anything to do so. Andrewa (talk) 15:29, 7 November 2015 (UTC)[reply]


Radio (receiver) → Radio receiver – Best name for the article. 2602:306:3653:8920:AC9C:7705:4648:749A (talk) 21:27, 30 October 2015 (UTC)[reply]

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

History section rewrite

Completely rewrote and expanded the largely unsourced, uneven "History of radio receivers" section including adequate sourcing. Renamed section "History" to remove unnecessary redundancy per MOS:HEADINGS. I'm not done with it yet, I plan to add some sourcing, rewrite the "Semiconductor era" subsection, fill in some missing stuff like FM receivers, and improve the placement of the images. --ChetvornoTALK 23:10, 23 February 2016 (UTC)[reply]

The original outline was sourced to this, but much thanks for your excellent rewrite. - LuckyLouie (talk) 00:09, 24 February 2016 (UTC)[reply]
The rewrite looks good and it helps to spread out over several sources. Fountains of Bryn Mawr (talk) 16:14, 24 February 2016 (UTC)[reply]
@Fountains of Bryn Mawr: (was computerless for a while) Thanks. I know some of the long strings of citations amount to WP:REFBLOAT - will be trying to cut them back (although I find that hard to do after I looked them up!). --ChetvornoTALK 21:13, 6 April 2016 (UTC)[reply]
@LuckyLouie: Sorry, you're right. I didn't mean to imply that the previous version was bad. --ChetvornoTALK 21:13, 6 April 2016 (UTC)[reply]
The referencing looks fine, glad to be able to look up the sources used. Very helpful. Fountains of Bryn Mawr (talk) 00:53, 7 April 2016 (UTC)[reply]

WikiProject Russia

Why is this article within the scope of WikiProject Russia, which is "a WikiProject dedicated to coverage of Russia"? Lambtron (talk) 21:46, 6 April 2016 (UTC)[reply]

The reason it might be there is because the USSR claimed radio as their invention via Alexander Stepanovich Popov and the adding editor may have thought this article should "claim" a Russian invention. It may be still applicable in that Popov's device may have been the first application using a radio wave receiver in something other than a science experiment (as a lightning detector designed to work in the field). I don't know if the scope of the WikiProject Russia is intended to cover such a distinction, or if there is a strong enough claim re: Popov, but worth looking into. Fountains of Bryn Mawr (talk) 00:53, 7 April 2016 (UTC)[reply]

Section title formatting

@BrydoF1989: The reason I used the distinctive formatting is that the History section contains a lot of subsections under three main section headings, and without format differences the main section heads are hard to recognise among the subsections when scrolling through the article. You may have noticed, one problem with WP markup is that the visual difference between lower level subheadings is pretty small, just a slight difference in font size:

Heading level 3

Heading level 4

Heading level 5

When separated by large blocks of text it is hard to distinguish what level a section head is at. --ChetvornoTALK 07:48, 2 December 2016 (UTC)[reply]

Since there is no reply I am going to restore the original formatting. --ChetvornoTALK 04:17, 9 December 2016 (UTC)[reply]
I think the lack of visual distinction between higher-order headings is a subtle reminder to simplify the article. We're not writing the tax code here -if you need that many subordinate sections, time to spin something out to a separate subordinate article. If book, chapter, and verse were good enough to organize the Bible, it should be good enough for this place. --Wtshymanski (talk) 19:25, 10 June 2017 (UTC)[reply]

Page history

Some old history that used to be at the title "Radio receiver" is now at Talk:Radio receiver/Old history. Graham87 03:54, 24 December 2016 (UTC)[reply]

Recent change to introduction

I am concerned about the recent edit to the introduction, which replaces this description of a receiver's operation:

"The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation."

with this:

"The antenna intercepts radio waves (electromagnetic waves) and passes them to the detector, which converts the waves into tiny alternating currents which are then applied to other parts of the receiver, and the desired information is extracted. The receiver uses a tuner to separate the desired radio frequency signal from all the other signals picked up by the antenna. An RF (radio frequency) amplifier increases the power of the signal for further processing, and finally recovers the desired information through demodulation."

I think the original wording is more accurate and should be restored. Here are my objections to the new wording:

  • The first sentence says "electromagnetic waves" are passed to the detector which converts them to "alternating currents". The antenna is the device which converts electromagnetic waves to currents.
  • The first sentence says the first component of the receiver is the detector. While the mixer in a superheterodyne receiver is sometimes called a "detector", the term "detector" is more usually used for the demodulator at the end of the signal chain. Also, in most superheterodynes the antenna signal is first applied to an RF amplifier. More generally, this article is about all receivers, not just superheterodynes, and in other receivers, for example the TRF, the RF amplification occurs before the detector.
  • The third sentence says "an RF amplifier increases the power of the signal for further processing" AFTER it passes through the detector. If this is referring to the IF amplifier in a superheterodyne, it is not called an "RF amplifier". And again this article is not just about superheterodynes but all receivers; in most receivers the RF amplifier is not after the detector but before it.
  • In contrast, the original wording did not specify the order of the operations performed, but just listed them, and so applied adequately to all receiver architectures.

--ChetvornoTALK 19:02, 29 March 2018 (UTC)[reply]

portable radio

It seems that portable radio redirects here. It would be nice to have some description of the evolution from vacuum tube based portable receivers though transistorized models. Gah4 (talk) 02:06, 23 May 2019 (UTC)[reply]

Radio was in a sense always portable, with batteries as a power supply. There was never a time when you couldn't put them on horses [2] or take them to the beach [3], etc. so any "evolution" of portable radio would naturally correspond with the evolution of radio technology itself. If you are referring to commercial evolution of the portable radio, then there are probably a few retail model examples that represent the shift from tubes to transistors to ICs. - LuckyLouie (talk) 13:45, 23 May 2019 (UTC)[reply]
In the days of CRT television sets, anything with a handle on top counted as portable. So yes, it seems that Armstrong's beach radio is portable. But I thought that there were smaller ones, especially from the days of miniature vacuum tubes, that made it to the retail market. I do remember back to tabletop tube radios and hifi systems. We never had any such portable tube radios at home, though. Gah4 (talk) 23:38, 23 May 2019 (UTC)[reply]
Some useable content could probably be gleaned from this: [4]. - LuckyLouie (talk) 23:58, 23 May 2019 (UTC)[reply]
OK, here's a start [5]. Not sure if the new section is ideally located, but feel free to tweak. - LuckyLouie (talk) 13:27, 24 May 2019 (UTC)[reply]
Looks good. That article on "lunch box" radios is interesting. One of the reasons vacuum tube radios were large and heavy was they required at least two heavy, bulky batteries. The "A" battery, consisting of one or two dry cells, provided 1.5 - 3v at several amps for the tube filaments. The square "B" battery provided 30 - 45V for the tube anodes. Some radios required a third "C" battery for grid bias. --ChetvornoTALK 19:03, 24 May 2019 (UTC)[reply]

familiar

I think the new description on familiar instead of common is good, though I am suspecting that TV sets are more familiar, and people do know that they need to tune (channel select) them. For things like WiFi, Bluetooth, and RF based remote controls, people don't normally tune them, so are less likely to think of them as radios. Can we mention both broadcast radio receivers and TV sets? Gah4 (talk) 01:09, 15 October 2019 (UTC)[reply]

My feeling is the introduction should be written for non-tech-savvy general readers, including Sociology majors and high school dropouts, particularly in a broad introductory article like this. A television is not called a "radio receiver" in ordinary language, and I think there are many people who don't know it is a radio receiver, particularly since only a small fraction of TVs are now used for over-the-air reception. The problem is in ordinary English the word "radio receiver" is used exclusively for audio receivers, the most familiar of which is the broadcast radio receiver. That is what this sentence is saying. I believe there is a significant segment of readers who are unaware of the broader, technical definition of a radio receiver as any device for receiving radio waves. This paragraph is aimed at correcting this misconception. I wouldn't mind adding the word "television" to the last sentence in the introduction, to address its wide use. --ChetvornoTALK 00:40, 16 October 2019 (UTC)[reply]
Good improvement by Chetvorno. BTW, radio receivers (albeit satellite models) are still a familiar and specific thing for most people who drive or ride in automobiles. - LuckyLouie (talk) 01:15, 16 October 2019 (UTC)[reply]
Looks good to me. Gah4 (talk) 08:04, 16 October 2019 (UTC)[reply]

Data?

All data *must* be digital? A generation of radiosondes sent their measurements back in vain, then? --Wtshymanski (talk) 17:43, 22 December 2019 (UTC)[reply]

Indeed. Wording could be better here, so it highlights that both have been part of radio history, but that much has quite recently shifted to specifically digital data, and also using "data" as an encoding mechanism for other content, such as audio, rather than v.v.
Interestingly there's also something of an analogue revival going on at present, at least in bird and small animal tracking, as a means of reducing the power demand for transmitters. Some old greybeards are having to be hauled out of retirement to work on it (and how many times have I said "You should use a Kalman filter for that" recently?). Andy Dingley (talk) 17:56, 22 December 2019 (UTC)[reply]
But the vast, vast majority of data communications is digital. The few non-digital data telemetry protocols are mostly legacy systems, like the old comutator-operated radiosondes Wtshymanski mentions. The largest use of radio transmitters and receivers today is probably in wireless modems, but I doubt if the general public connects the term "radio receiver" with wireless digital devices. That's my reason for including the word. --ChetvornoTALK 18:00, 23 December 2019 (UTC)[reply]
I suppose we could say “digital or analog data” to cover both modern and legacy applications. - LuckyLouie (talk) 18:15, 23 December 2019 (UTC)[reply]
My feeling is that would mislead general readers. It seems to me the number of systems that transmit "analog data" is so small as not be notable enough to mention in the introduction. So if the consensus is against "digital data" I would prefer "data". --ChetvornoTALK 20:46, 23 December 2019 (UTC)[reply]
It is an unlovely habit of WP to use the form "yang or yin" as a qualifier. "Apart from the known, and the unknown, what else is there?" Storage is free, and editors are disposable, but hypothetically we are writing for readers with finite life spans. --Wtshymanski (talk) 17:48, 24 December 2019 (UTC)[reply]
I have no idea what you are talking about. Could you be a little clearer? --ChetvornoTALK 20:05, 24 December 2019 (UTC)[reply]
It's all right, you can always get me suspended again if you disagree with me. "Digital data": is inaccurate and a useless qualification on what gets sent by radio; "data" would be perfectly adequate, but has been shouted down by the great consensus. And "analog or digital" data would be a perfectly Wikipedia way of saying nothing in the maximum possible number of words. --Wtshymanski (talk) 01:41, 28 December 2019 (UTC)[reply]
If it was just readers like you and I, yes, I would agree with you. But the introduction should be written for general readers, including high school dropouts and ballet majors. That means explaining on a level that seems wordy and redundant to you and I. "The information produced by the receiver may be in the form of sound, moving images (television), or data." is terse and uninformative. Someone whose only experience with receivers is a bedside clock radio may have the impression the only thing a receiver can do is play audio content from a radio station. Their reaction is likely to be "Data? I have no f**king clue what this is about." I would actually like to expand this sentence to something like "...data, such as from wireless computer devices". Then the reader says to himself "Oh yeah, my iPad, maybe it works by radio".
And I agree with you about "analog and digital" that doesn't really improve comprehension.--ChetvornoTALK 11:18, 30 December 2019 (UTC)[reply]
And I didn't get you suspended, I don't know where that's coming from. --ChetvornoTALK 11:18, 30 December 2019 (UTC)[reply]
I see, , "data" by itself is strange and terrifying but "digital data" makes it all better and comfy. And so it grows. --Wtshymanski (talk) 22:32, 30 December 2019 (UTC)[reply]

A Commons file used on this page or its Wikidata item has been nominated for deletion

The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 19:36, 9 July 2022 (UTC)[reply]

Disputed section on audion

This section is largely inaccurate mostly because the modern interpretation of the historical sequence of events is not correct. Almost anyone today will tell you that De Forest invented the triode vacuum tube. He did not. He invented the audion tube which contained low pressure gas (probably air). It was a better detector that the diode type detectors previously available because it amplified the detected signal. However, the modus operandi of the audion was completely different to the vacuum triode. The audion was very non linear and as such was completely useless for further amplification. Even its amplified detected signal was heavily distorted. Speech was still intelligible though music would have been impossible to listen to (though at this time, any entertainment application for radio was still in the future).

The position was further confused because when Langmuir invented the vacuum triode, De Forest (who did not even understand how his own audion worked) believed that Langmuir had stolen his invention simply because they looked the same (and he did not understand how the vacuum triode worked either). It is now known that De Forest was only interested in exploiting any technology to make money (one area in which he did have expertise) and to earn himself fame to boot.

De Forest could not possibly have invented the vacuum triode when he invented the audion because the mercury diffusion vacuum pump which was required to produce the required vacuum was invented at about the same time in Europe, so he would have been unaware of it.

The audion was unstable but not for the reasons stated in the article. Like the X-ray tubes of the same period, the bulb of the device got hot and this caused the low pressure gas filling to be adsorbed into the glass and the metal components. Ironically, this caused the audion to slowly turn itself into a vacuum triode. De Forest lacked the technical knowledge to understand why his audions failed, which is probably why it never occurred to him to put a re-gassing device on the bulb similar to the ones fitted to the X-ray tubes of the time.

Another contributor wrote a potential article on the modus operandi of the audion and the differences to the vacuum triode. Unfortunately, I do not know if it still exists or where it was located (it never made it as an article, IIRC, mostly because references were hard to find).

Note: that Edwin Armstrong's paper on the audion was not produced as a scientific peer reviewed paper. It was produced as part of an evidence trail in another patent dispute where De Forest was claiming that he had invented something that he had not. The paper was intended to demonstrate to a judge that De Forest had insufficient technical understanding about his audion let alone anything else. It may, therefore, not be entirely correct.

De Forest famously stated that "I have no idea how it [the audion] works. It just does". 86.162.147.159 (talk) 13:25, 8 October 2022 (UTC)[reply]

It does seem likely that he didn't have as good a vacuum as would have been desired. But we need some actual WP:RS about it. Gah4 (talk) 19:24, 8 October 2022 (UTC)[reply]
The Audion is considered the first triode:
  • "On October 25th,...De Forest of the USA made his application for American patent of triode..." Okamura, History of Electron Tubes, p.97. "De Forest's triode was also called an Audion..." p.325 [Okamura continues to refer to De Forest's 1907 Audion as a triode many times.]
  • "De Forest invented the three-electrode valve or vacuum tube triode." Sarkar, History of Wireless, p.100. "This triode device he [De Forest] termed the "Audion"." (p.325) "In the same year, Lee De Forest, the so-called Father of Radio, invented the transmission grid triode..." (p.335) Calling it a Three-Electrode Audion (patent issued on February 18, 1908), de Forest referred to it as a “device for amplifiing feeble electric currents”
  • "Without wishing to detract from the importance of the diode, it was the Audion - or triode - that revolutionized wireless..." Wood, History of International Broadcasting, p.9
  • "The year 1907 saw the invention, by Lee De Forest, of the first electronic device capable of amplification; the triode vacuum tube." Lee, Microwave Engineering, p.11
  • "...in 1906 - only three days, in fact, before he resigned from the company - he [De Forest] had conceived the first triode vacuum tube and given orders for its manufacture." Aitken, The Continuous Wave, Technology and American Radio, p.195. "The first public display of the triode audion was at a lecture before the Brooklyn Institute of Arts and Sciences on 14 March 1907" {p.222) [The text uses the term "triode audion" to distinguish De Forest's tube with the third electrode inside the tube from his earlier tubes with the third electrode outside, which were described on earlier pages.]
  • "In 1907-1908 American inventor Lee De Forest inserted a third electrode between the cathode and the plate. De Forest called his device the "Audion" but it is now called the triode" Nahin, The Science of Radio, p.106
  • "The history of inventions is almost always clouded with claims and counterclaims and embellished with legend... So it is with the case of the thermionic triode, which Lee De Forest invented in 1906 as a detector of wireless-telegraph signals." Robert Chipman, "De Forest and the Triode Detector", Scientific American, March 1965, p.93
  • "In 1907, he [De Forest] patented a much more promising detector which he called the Audion... It was a thermionic grid triode vacuum tube..." Lee De Forest, Encyclopedia Britannica online
  • "Yet De Forest's trade name would disappear; in later years the Audion would be known as the "triode" because of its 3 internal elements" Morton & Gabriel, Electronics: Life Story of a Technology, p.8
  • "De Forest... applied for a patent on October 25, 1906 for a "three-electrode valve..." He called his device the Audion. Thus the triode was created and the electronic era started..." Huurdmann, The Worldwide History of Telecommunications, p.226
  • "In 1906-1907 De Forest introduced a third electrode, the grid... This triode, which De Forest called the "audion", not only rectified but also amplified the signal from the aerial. These early handmade valves contained a fair amount of gas and so varied in their working characteristics. H. J. Round... and Robert Lieben... developed similar "soft" triodes. Heilbron, The Oxford Companion to the History of Modern Science, p.819
  • "The audion was also called the triode" Hong,Wireless: From Marconi's Black Box to the Audion, p.223
--ChetvornoTALK 22:47, 8 October 2022 (UTC)[reply]
All of this just underlines how the differences between the audion and the true high vacuum triode have been lost to history. As I said: the main issue is that although they looked identical in construction, they were distinctly different devices having modus operandi that were completely different, along with entirely different characteristics and different bias requirements. For example: the vacuum triode requires a steady negative bias to its grid. None of De Forest's circuits for his audion show any bias at all because it was not required. In fact, any negative bias would stop the audion from working which was its primary failure mode because the grid would develop its own negative bias as the gas pressure dropped as it aged. 86.162.147.159 (talk) 12:13, 9 October 2022 (UTC)[reply]

OK, there was the Mercury rectifier which traces back pretty far, and with different physics from the vacuum rectifier. There are, however, different questions. A favorite trick in chemistry patents is to add a methyl group somewhere, and patent the new molecule. That tends to work, even when the actual active mechanism is the same. So, the exact difference needed to get a new patent might be different from the actual physics. But an any case, we need a WP:RS. Gah4 (talk) 21:40, 9 October 2022 (UTC)[reply]

You obviously failed to read the OP. You are also discussing obtaining patents in the US where you can pretty well patent anything you want (and have to slug it out in the courts). Elsewhere in the world, you only get a patent if you actually have anything genuinely new to patent. I have had three - excluding the one that was turned down because the patent office found a similar prior application. One, although for a different but not unrelated, device might have been applicable to genuine audion based circuits though their inherent instability would probably have rendered it moot. 86.162.147.159 (talk) 17:07, 10 October 2022 (UTC)[reply]
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