Talk:Crystal detector

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Verifiable Name: Crystal Detector[edit]

January 22, 2018 - "Cat's whisker" refers ONLY to the fine wire or needle that contacts the crystal. The entire device, which this article is about, is a crystal detector. Publications contemporary to common use of this type of detector refer to it as a "crystal detector". For examples see "The Principles Underlying Radio Communication", 2nd Ed., Radio pamphlet no. 40. USA: Prepared by US National Bureau of Standards, United States Army Signal Corps. 1922. pp. 421–425 and F. J. Camm, "Practical Wireless Circuits", 1931, p.5. LSMFT (talk) 17:43, 22 January 2018 (UTC)[reply]

Move[edit]

Suggest we move this to Cat Whisker Detector. —Preceding unsigned comment added by JA.Davidson (talk • contribs)

You mean "Cat-whisker detector"? Dicklyon 05:15, 27 March 2007 (UTC)[reply]

Hyphenation[edit]

Are you sure about the hyphen in cat's-whisker. I understand the logic, but I don't recall ever seeing a hyphen with a possessive. Hyphens normally go between compound adjectives to avoid ambiguity. I guess there could be ambiguity: the cat's (whisker detector) or the (cat's whisker) detector. Still, I don't recall ever seeing this construction. SDC 05:07, 27 March 2007 (UTC)[reply]

I checked first with Google Book Search. It is of course common for many books to omit the hyphen in such constructions, since book authors and editors aren't completely literate on the whole, but since a fair number of them did use the hyphen, and since many of the ones that did use the hyphen used quotation marks as in "cat's whister" detector, it seemed clear that there was a consensus that this was not to be written as a detector of cat's whishers as we had before (or was it a detector of whiskers, of by or for the cat?). I thought the conventional hyphen made more sense than putting quotation marks into the title. Dicklyon 05:13, 27 March 2007 (UTC)[reply]

Crystal Radio circuit[edit]

My purpose in adding the circuit(cct) diagram file:Detector receiver rus standart.svg was to supplement the technical description in the de-modulation diagram above it. I believe that it makes more sense with a diagram to show what the description says. Another editor removed it, another added it again, and they had an edit summary 'discussion' on the merit of having a cct. diagram. I think a circuit, perhaps with a legend saying what the components are/do, as per the de-mod diagram, has value. Version with cct diagram. Any comments welcome! - 220.101 talk\Contribs 07:00, 4 October 2010 (UTC)[reply]

If you cite a source that mentions crystal detector or cat's whisker and shows such a schematic, then that should be sufficient justification. I find plenty of books like this one and this one. The latter illustrates waveforms at different points in the circuit. Dicklyon (talk) 23:04, 4 October 2010 (UTC)[reply]
It would be best if one could find a schematic of an actual cat's whisker detector set - I don't think the variable capacitor beloved of 21st century textbook authors was a common component of a cat's whisker receiver. --Wtshymanski (talk) 00:54, 5 October 2010 (UTC)[reply]
The variable capacitor was a mid 20th century innovation. The radios I built around 1960 used a variable coil, more like this one. Dicklyon (talk) 03:49, 5 October 2010 (UTC)[reply]
This one from 1943 (see this search with snippet) says "comprises a fixed inductance, a variable tuning capacitor, an adjustable 'cat- whisker' type of crystal". Dicklyon (talk) 03:54, 5 October 2010 (UTC)[reply]
Here's one, but the coil is a transformer. Dicklyon (talk) 03:56, 5 October 2010 (UTC)[reply]
Can't see anything in the snippet view of the first and don't have access to a paper copy. The transformer in the second is important; from what I've read, most of the capacitance of a typical cat's-whisker receiver is between the antenna and ground, so a variable capacitor is useless in affecting the tuning. When cat's whisker detectors were a viable product, as opposed to the demonstration of principles that they must have been by 1943, one would not have manufactured a crystal set with a variable capacitor. My point ( and I do have one), is that it is misleading to the reader to show a "modern" LC tuned circuit as if this was the circuit actually used when cat's whisker detectors were used in earnest, not as hobby demonstrations of a concept. --Wtshymanski (talk) 13:10, 5 October 2010 (UTC)[reply]
And for completeness...I also don't think that schematic drawings have much explanatory power to the general reader not already familiar with the symbols and conventions. If you've been reading Turkish all your adult life, you may not even notice how incongrous it is to have a Turkish paragraph in the middle of an English-language article. --Wtshymanski (talk) 13:25, 5 October 2010 (UTC)[reply]
One of the things I tossed out as a kid that now I wished I'd saved was a real "cat's whisker" set found in an old house my parents tore down when we bought the place. I don't know if it was a commerical product or very good home brew (it had no nameplate on it that I recall), but it had a wound coil with a slider for a tuner. The coil former wasn't a piece of an oatmeal box, but was about that size, mounted in some nicely rabbeted wooden end pieces. The galena crystal was in a little metal pot in solder, on a bakelite base with a lever and whisker to probe the surface. All the parts were mounted on a little board with Fahnestock clips (of course we have an article on that) for antenna, ground, and headset connections. For sure it had no variable capacitor but I no longer recall if it had any fixed capacitors. In school shops I built almost a replica with a much smaller coil and a 1N34 diode; as I recall it could only get one station no matter where I put the "tuner", but worked OK for that station. I suspect now that the coil was too small for the antenna I was using, though as a kid I never figured this out. Someone gave me a kit for Christmas which was the same idea; slider on a coil, no capacitors, but a very elaborate plastic case (and a useful high impedance headphone which may still be sitting in a box somewhere in my junk collection). Three crystal sets, one honest-to-Jimbo cat's whisker set, and no tuning capacitors in the lot. --Wtshymanski (talk) 13:50, 5 October 2010 (UTC)[reply]
(outdent) Problem solved! Crystal set had the correct diagram. Pictorial, so it doesn't obscure with runic symbols. And authentic, so we don't lie to the reader. --Wtshymanski (talk) 14:04, 5 October 2010 (UTC)[reply]
This one?
You mean this one?: File:CrystalRadio.jpg I missed out on this discussion, but I did find this excellent PDF of "The 'P.W.' Crystal Experimenters Handbook" which came with the October 1923 issue of "Popular Wireless" "Xtal Experimenters Handbook" (PDF).. Fig.8 p.22 is a more complicated cct than the one I added, but has a variable cap. and certainly appears to refer to a cats whisker (Galena) as the detector. See also Fig.8 p.20 Variable caps seem to have been around in the early 1920S. See See Page 5 (Fig. E) of Crystal Clear: Vintage American Crystal Sets, Crystal Detectors, and Crystals By Maurice L. Sievers. nb. Variable capacitor has no history information at all. :-( But it appears they were used as early as 1923. ☢ 220.101 talk\Contribs 08:34, 6 October 2010 (UTC)[reply]
The notion of a variable capacitor probably goes back to the Leyden jar when the size of the spark depended on the water level in the jar. --Wtshymanski (talk) 13:16, 6 October 2010 (UTC)[reply]
Whoops, didnt notice you had already put it in! Layout needs work though!- 220.101 talk\Contribs 08:45, 6 October 2010 (UTC)[reply]

Redundant?[edit]

Does this topic deserve to be separate from the article on Crystal Radio? John (talk) 21:32, 5 October 2010 (UTC)[reply]

If Crystal radio wasn't already 75 k (mostly due to a surfeit of low-value citations that could be combined), I'd agree with you. That article needs to have some of the redundant text about materials moved to this article, at least. --Wtshymanski (talk) 01:21, 6 October 2010 (UTC)[reply]

German microwave detector[edit]

IIRC, the a German worked on microwave detectors, but stopped that research for ethical reasons. British radar developers needed better detectors and somehow stumbled upon the research. Glrx (talk) 17:09, 25 June 2012 (UTC)[reply]

Image for Crystal Detector function is inaccurate.[edit]

I presume you mean this picture, no?

The image for a crystal detector on a radio has several inaccuracies.

First, it shows the output of a full-wave rectifier, when a simple crystal detector is a half-wave rectifier.

Second, it shows the final demodulation as peak values of the rectified signal, not RMS averaged. If the waveform is stabilized by the high-pass filter effect of the crystal rectifier diode it is going to result in the RMS of the waveform, not the peak values. — Preceding unsigned comment added by RuediiX (talk • contribs) 20:57, 6 May 2013 (UTC)[reply]

The picture shows half-wave rectification and peak following, more or less. There's no reason to expect you could get rms out of such an arrangement (and every reason to expect that getting rms is quite difficult with rectifiers of any sort), and a peak-following diode/capacitor circuit would more nearly follow the peaks of the envelope. What exactly a crystal would do is hard to guess. Dicklyon (talk) 02:49, 8 May 2013 (UTC)[reply]
First, as Dicklyon says, the figure suggests half-wave rectification that would result from an ideal diode; it is not a full wave rectifier.
Second, I don't know if the (unamplified) cat's whisker circuits operated as low-level square-law detectors (first two terms of the Taylor series expansion of the diode nonlinearity; the diode looks like a non-linear resistor) or high-level (quasi-ideal diode) detectors. The question is what voltage does the crystal detector see. Depending on the received signal level (field strength and effective antenna height), the impedance transformation (e.g., 2K electromagnetic headphones or 50K piezo headphones), and the Q, crystal detectors could operate in both modes.
The radio reception explanations that I remember are the high-level peak detector / envelope detector with a leaky hold capacitor. The article's illustration comes from a 1922 book.[1] That book uses an ideal diode description (current flows one way). The text shows the recovered audio matching the shape of the envelope, but it does not say peak detector, and the book doesn't show the recovered audio being the same amplitude as the RF. (Figure 27 does not show any absolute scales.) (I don't like the figure 30 receiver circuit.) Many early designs used the headphone as a low pass filter, so they worked as an average detector rather than a peak detector. The peak v average distinction only introduces a scale factor. I'm not happy with the notion of a peak detector in a crystal radio; there are some subtle issues about getting enough energy to charge the hold capacitor; it's a good thing that there are many RF cycles available for charging, so it can work. There are many other issues.
In any event, WP needs sources. Terman (1943 p. 566) only devotes two paragraphs to crystal detectors, states that Galena is less stable than silicon, claims that Galena is a better low-level detector than silicon, and offers the comment "The only use of crystal detectors at the present time is in ultra-high-frequency work, because they will function at frequencies where transit time effects in [vacuum tube] diodes are excessive." Terman cites (but I haven't dug up)
  • F. M. Colebrook, "The Rectifying Detector", Exp. Wireless and Wireless Eng., volume=2 page 330 March, page 394 April, page 459 May 1925.
I've seen discussions of square-law detection in the context of microwave measurements. I don't recall seeing much literature on cat's whisker detectors (a ca 1925 NBS circular may have a crystal IV curve). I don't recall any literature covering signal levels in a crystal set. If sources can be found, then more detail can be added to the article.
Glrx (talk) 17:38, 8 May 2013 (UTC)[reply]

Antique ?[edit]

Not even a 100 years ... That word references the centuries B.C. of the Greek and Roman empires and Wikipedia is assumed to be a serious publication ... I would rather tend to use words like "outdated" or "1. generation" or so ... JB. --92.195.103.219 (talk) 03:48, 29 March 2015 (UTC)[reply]

Removal of name 'cat whisker detector'[edit]

User:LSMFT recently removed all mention of the name "cat whisker detector" from the article. I think this should be reverted.

"...significant alternative names for the topic should be mentioned in the article, usually in the first sentence or paragraph. (MOS:ALTNAME) "Cat whisker detector" is clearly a significant alternative name for this device. In the first place, inventor Greenleaf Whittier Pickard branded it as "cat whisker detector" when he invented it. Second, the name stuck: in addition to the name "crystal detector", numerous wireless books of the time call it a "cat whisker detector". Third, even if they didn't, numerous modern reliable sources, technical and historical books and websites, call it a cat whisker detector (in modern sources the alternate form "cat's whisker detector" is usually used). This article is not about modern semiconductor diodes, which have their own article. The name "cat whisker detector" is used to distinguish the historical device from modern diodes which are sometimes also called "crystal detectors" when used in crystal radios. Here are sources supporting these points:

Although there are many sources that don't use this name, LSMFT has given no sources that say "cat whisker detector" should not be used. Omitting this widely used alternate name from the article is grossly WP:POV. --ChetvornoTALK 20:36, 1 May 2018 (UTC)[reply]

  • Keep Cat's whisker detector is well-documented, historical (at least) and understood. Removing it is a disservice to our readers. 7&6=thirteen (☎) 15:37, 2 May 2018 (UTC)[reply]
  • Keep cat's whisker. It was the common name the detector when they were still being used. My uncle made one when he was a kid. Glrx (talk) 16:17, 2 May 2018 (UTC)[reply]
  • Keep per Glrx's uncle. Now here is the scary part - I made one! It was definitely called a cat's whisker detector when I was ten years old. Yikes. Oh and by the way - they actually worked. My first radio stations I heard came off a cat's whisker detector - the first true solid state device.--Doug Coldwell (talk) 17:30, 2 May 2018 (UTC)[reply]
Wow. Did you use galena? How difficult was it to use? When I was a kid somebody gave me a galena detector, but I never got it working. --ChetvornoTALK 01:15, 3 May 2018 (UTC)[reply]


I think the lead sentence should be changed to limit the scope of the article. The current lead gives no indication that this is an obsolete antique device and seems to cover modern semiconductor diodes, and even uses outside radio receivers:
"A crystal detector is an electronic component used to rectify radio frequency alternating current."
I think the article should be limited to antique point contact diodes, and the lead should be restored closer to what it was originally:
"A cat-whisker detector (sometimes called a crystal detector) is an antique electronic component consisting of a thin wire that lightly touches a crystal of semiconducting mineral (usually galena) to make a crude point-contact rectifier."
The problem is the term "crystal detector" is overinclusive. It originated with the cat-whisker detector, but continued to be used for more modern semiconductor detectors used as demodulators through electronics history: carborundum cartridge detectors, the germanium point contact diodes used in radar receivers in WW2, [2], [3] and still is used for the semiconductor diodes in modern crystal radios. [4] I think the introduction was changed in an attempt to cover this range of usage. Perhaps the article should be moved back to the title Cat's whisker detector where it was originally? --ChetvornoTALK 01:15, 3 May 2018 (UTC)[reply]


Editor Chetvorno, et al.: At the time I wrote the Jan. 22 passage above, the article did not cite any sources for the term it used, "cat's whisker detector", and I had not seen the sources showing use of the term "cat-whisker detector" such as A.P. Morgan, Wireless Construction and Installation for Beginners, 1914. Additionally, the term I removed was "cat's whisker detector", not "cat whisker detector".

I have learned that a cat-whisker detector is definitely a particular type of "crystal detector". The article as it was on 5 Dec. 2017 included more than only the cat-whisker detector, its contents included various other embodiments of crystal detectors that are NOT cat-whisker detectors (as the article still does as of 3 May 2018). I think it would be reasonable to have an article limited to ONLY cat-whisker detectors or to include cat-whisker detectors as a particular section of a crystal detector article, which would include other sections for other crystal detector embodiments.

Could someone please direct me to the publication in which G. W. Pickard used the term "cat whisker detector", as I would very much like to see it. Thank you,LSMFT (talk) 03:20, 3 May 2018 (UTC)[reply]

Okay, I understand your position. I didn't mean to accuse you of anything. I wrote a good deal of the current article, and did not include sources; I'll work on adding them. While the article started with traditional "cat whisker" detectors, consisting of an adjustable wire touching a crystal, other related devices seemed to be part of the same technological family so I included them: Pickard's Perikon detector consisting of two crystals touching, and the sealed carborundum cartridge detector used in 1920s radios, consisting of a nonadjustable point contact. I chose not to include the lead peroxide detector [5], [6], [7] because it is not a point-contact device. This is a common problem in history of technology articles - trying to decide how far along a continuous line of development a particular name or label applies. --ChetvornoTALK 20:54, 5 May 2018 (UTC)[reply]
My feeling is the scope of this article should be limited to the above devices: historical point contact semiconductor detectors before the rise of solid state electronics, say up to the 1930s. Later semiconductor detectors, such as the germanium point contact crystal detector used as a demodulator in World War 2 radar sets, should come under Diode#Point-contact diodes. (I have no objection to the History section's including an account of these subsequent point contact diodes, nor the pictures of modern reproductions of cat whisker detectors). I don't think it makes sense to have separate articles for "cat whisker" detectors, the Perikon crystal-to-crystal detector, the carborundum wide-contact detector, and the cartridge point contact detector; these are all part of the same technological family. --ChetvornoTALK 20:54, 5 May 2018 (UTC)[reply]
The term "crystal detector" was the original and most widely used name for these early semiconductor detectors, and nicely covers all the varieties. The problem is it's usage has been expanded through history to include all subsequent semiconductor junction detectors - germanium radar diodes [8], video detector diodes [9], modern crystal radio diodes, etc. For that reason I think it is too inclusive to use as the title of an article. Therefore my preference for the name of this article is "Cat's whisker detector" (or "Cat whisker detector", I don't care). Not all the devices in this article have a "cat whisker" contact, but the term never had an "official" definition, and I think it's the best name for this family of devices. "Crystal detector" should be included as an WP:ALTNAME. If the consensus is to continue using the name Crystal detector I won't object, but I do object to extending the article to cover both antique and modern crystal detectors; that would be too redundant - we already have Semiconductor diode, Semiconductor junction, Demodulator and Detector (radio). --ChetvornoTALK 20:54, 5 May 2018 (UTC)[reply]

Recent edits and page move[edit]

I have some objections to the recent edits of LSMFT

  • What is the purpose of the page move to Crystal detector (radio)? Is a crystal detector ever used for anything besides demodulating radio signals? The two pages Crystal detector and Crystal detector (radio) are going to be confusing for nontechnical readers, and increase the redundancy in this area: we already have Diode, Semiconductor junction, Rectifier#Crystal detector, Demodulator, and Detector (radio). It does nothing to solve the main problem with the term "crystal detector" as an article name; that it is applied to both modern and historical devices. --ChetvornoTALK 22:25, 5 May 2018 (UTC)[reply]
  • Describing the crystal/cat whisker construction under the section Galena detector is misleading and unhistorical, implying that only galena detectors were constructed this way. Although galena was the most popular, a variety of crystals were used with the cat whisker: iron pyrite, molybdenite, titanium dioxide, tellurium, and manganese dioxide. [10], [11] --ChetvornoTALK 22:25, 5 May 2018 (UTC)[reply]


Hello Editor Chetvorno,

  • Creation of a page titled something like "Crystal detectors prior to A.D. 1930" (or 1940 or whatever year would be closely prior to the intensive 20th century research to develop detectors for UHF and shorter wavelengths) containing most of the material from the "Crystal detector (radio)" page seems reasonable.
  • At the time I moved the page in January I did not that there was already a Crystal detector page (I'm quite a neophyte at this Wikipedia editing stuff).
  • My intention was to continue adding subsections for different crystal detector embodiments under "Types" and move "Galena Detector" farther down in the list, did not have time yesterday, e.g.,
  • Types

(Intro paragraph similar to 5 May 2018 version) (could also include paragraph on types of moveable contacts used (cat whisker, needle, crystal to crystal, etc.)

  • 2.1 Silicon Detector
  • 2.2 Zincite-Chalcophyte Detector
  • 2.3 Carborundum Detector
  • 2.4 Iron pyrite Detector
  • 2.5 Galena Detector
  • 2.6 Etc. Detector

Thankyou, LSMFT (talk) 13:45, 6 May 2018 (UTC)[reply]

I don't think the articles should be WP:Forked and fragmented. Develop the existing article. 7&6=thirteen (☎) 14:42, 6 May 2018 (UTC)[reply]
I don't have the time now to thoroughly digest the debate, but the current article should not be forked and fragged. There might be reason to split off an article later.
This article should not be Crystal detector (radio). There's no reason for the "(radio)" DAB; no other "crystal detector" is vying for the name. Cat's whisker may have been too specific for the technologies covered, but it did set the time period of the technology. If I thought about it more, I'd probably WP:RM the article. WP does not name articles "Crystal detectors prior to A. D. 1930".
Although there are modern "crystal radios", they use germanium or Schottky diode detectors. We don't call a 1N34 a crystal detector; it is a germanium diode or a point-contact diode.
I doubt "galena detector" was a common name. I'd have to dig up some references for other variations such as silicon carbide.
In modern electronics terminology, "crystal" more often means "quartz crystal".
Glrx (talk) 17:19, 6 May 2018 (UTC)[reply]
@Glrx: While I think that's generally true, I'm seeing some usage of the term "crystal detector" for later devices, such as germanium radar detector diodes [12], [13], [14] and video detector diodes.[15], [16] I don't think the article should include these. --ChetvornoTALK 19:01, 7 May 2018 (UTC)[reply]
@Chetvorno: I'd only put weight on the first (Artech publisher), and it's from 1991. I put very little weight on Carr; he's written many books, but he's an experimenter and focused on older technology. Crystal detector conjures up an image of an old prospector using a divining stick to find a quartz crystal vein in the hopes of striking it rich. Glrx (talk) 19:22, 7 May 2018 (UTC)[reply]

Should we move it back to Cat's-whisker detector until such time as the content scope increases? Or move it to Crystal detector? Dicklyon (talk) 21:00, 6 May 2018 (UTC)[reply]

I'd say Crystal detector for now, and PROD Crystal detector (radio); there seems to be consensus that it isn't needed. --ChetvornoTALK 21:08, 6 May 2018 (UTC)[reply]
Editor Chetvorno's suggestion makes sense. Move to Crystal detector; PROD Crystal detector (radio). Thank you. LSMFT (talk) 21:35, 6 May 2018 (UTC)[reply]
  • (e/c) I'm OK with either Cat's whisker or Crystal detector. I can see advantages with either. CW coverage dominates the current article, and the carborundum detector needed power to bias it, so it would not see use in self-powered radios. CD has the broader scope. Glrx (talk) 21:39, 6 May 2018 (UTC)[reply]
@Glrx: @LSMFT: @Dicklyon: 7&6=thirteen: If the article name is Cat's whisker detector, would you be okay with including devices which don't technically have a cat's whisker, such as the Perikon zincite-chalcopyrite detector which used a crystal-to-crystal contact, or the carborundum detector, which used wide metal clamp contacts? I think all these devices should be covered in the same article, so that would be acceptable to me. --ChetvornoTALK 19:11, 7 May 2018 (UTC)[reply]
  • I'm OK with CW including other detectors that don't have whisker/needle/what have you. CW title suggests old-technology detectors; the name would be used not only for the particular detector but also the era. If a detector gets a lot of coverage later, it can be split off. Glrx (talk) 19:26, 7 May 2018 (UTC)[reply]
  • Editor Chetvorno, Editor Glrx: No wonder then that every time I look at a Wikipedia article I see how messed up and grossly WP:POV it is. Good luck. LSMFT (talk) 22:36, 7 May 2018 (UTC)[reply]
Well, that's why I'm asking, is there a better way? The consensus is to describe these devices in one article, but what name do we use? As you say, Cat's whisker detector doesn't really cover some of them, but the only other historical name, Crystal detector, is also used for some modern diodes. --ChetvornoTALK 00:03, 8 May 2018 (UTC)[reply]
If we used Cat's whisker detector I think we should make Crystal detector a redirect to this page and add it to the lead sentence as an WP:ALTNAME. That way editors of other articles could use crystal detector to refer to this page if they wanted. How would that be, LSMFT? --ChetvornoTALK 00:03, 8 May 2018 (UTC)[reply]
Crystal detector already is a redirect to this page. As I said above, I'm OK with either name. Glrx (talk) 01:49, 8 May 2018 (UTC)[reply]
  • Editor Chetvorno, Editor Glrx: My understanding my be mistaken, but at this time my POV is that an if an article is titled "Cat Whisker Detector" it should only discuss crystal detectors that incorporate a thin springy wire or wires to contact the crystal (see the description of "cat whisker" commonly found in books on the subject). "Cat Whisker Detector" or "Cat's", whichever, would have a link to a more general article, such as "Crystal Detector", which would discuss crystal to crystal contact, needle, large contact (carborundum), silicon, iron pyrite, later 20th century development (or link to such) and which would link to "Cat Whisker Detector". LSMFT (talk) 13:38, 8 May 2018 (UTC)[reply]
The title Crystal detector will certainly be preferalbe when the article has content beyond the cat's whisker variety, so why don't you go ahead and add some of that. No need to fork the current content to a separate article. Dicklyon (talk) 14:39, 8 May 2018 (UTC)[reply]
@LSMFT: I respect your position, even if I don't agree with all of it. I agree it makes sense to describe all these historical detectors in one "general article", as you say, whatever additional articles there are. They all did the same thing, worked the same way (semiconductor junction), were invented at around the same time, by some of the same people, competed with each other, and have the same significance in electronics history. If we divide this article up it will require a lot of redundant history in each subarticle, it will be complicated for other articles to refer to "crystal detectors", and readers will not be able to compare the devices and see the variety of detectors devised. Glrx, Dicklyon and 7&6=thirteen agree the article shouldn't be fragged. However if this "general article" also includes modern "crystal detector" diodes, this unity is lost. The article just becomes a mishmash with much duplication of content in Diode, Rectifier#Crystal detector), and Demodulator.
How about this. I would be willing to support keeping the article name Crystal detector if we limit the definition to historical (mineral crystal) detectors and include a hatnote at the top that says: "For modern crystal detectors, see Diode". I doubt it will stop editors from trying to expand the article to include modern diodes, but hopefully there are enough editors that feel the same way I do to defend this limitation. --ChetvornoTALK 16:54, 8 May 2018 (UTC)[reply]

I agree with the hatnote idea proposed by Chetvorno. 7&6=thirteen (☎) 17:25, 8 May 2018 (UTC)[reply]

I think I agree, too. It wasn't obvious to me what proposed new content was "modern" and what was "historical", but I think that's a good place to split. If Diode is not the ideal place for modern crystal detectors, then maybe another article is in order. Dicklyon (talk) 20:44, 8 May 2018 (UTC)[reply]
Then we can make a request at WP:RM#Uncontroversial technical requests for Crystal detector (radio) to Crystal detector. Glrx (talk) 22:55, 8 May 2018 (UTC)[reply]
Made the request. Glrx (talk) 23:03, 8 May 2018 (UTC)[reply]
Agree w/ deletion. @Dicklyon: Thanks for the input. My feeling is there is a natural break between "historical" and "modern" detectors around 1930, just before the germanium diode was developed. There's plenty of other articles besides Diode where modern crystal detectors could be put; Rectifier#Crystal detector, Detector (radio), Demodulator. I'm ok with any of them. --ChetvornoTALK 20:47, 10 May 2018 (UTC)[reply]

@LSMFT: how do you feel about this? --ChetvornoTALK 20:47, 10 May 2018 (UTC)[reply]

Thank you Editor Chetvorno, I like your hatnote suggestion. The Diode, point contact diodes, section would be a possible place to expand on rectifier development for radar and microwave applications. LSMFT (talk) 15:39, 11 May 2018 (UTC)[reply]
Editor Chetvorno, I thought of a better first sentence for the article, I'm happier with it now. LSMFT (talk) 23:34, 11 May 2018 (UTC)[reply]
@LSMFT: Thanks! That looks better to me, too. --ChetvornoTALK 01:19, 12 May 2018 (UTC)[reply]


@LSMFT: I don't mean to nitpick or WP:OWN the article, but I have some reservations about the wording in the introduction, although it is better than the previous wording:

  • In my opinion, the lead sentence, "A crystal detector...used in early 20th century technology wireless apparatus, is a device that rectifies... alternating current..." is too broad, and gives the impression that these devices were used as general rectifiers. They were used exclusively in radio receivers, as detectors, to rectify the radio signal, so I think the lead sentence should say that.
  • "Crystal detectors became very commonly used in early 20th century wireless receivers and crystal radios." Crystal detectors were almost exclusively used in unamplified "crystal radios"; there was little use in other "wireless receivers". Crystal radios were the reason for crystal detectors' WP:NOTABILITY, and I think the introduction should say a little more about them.
  • The term "cat whisker detector", bolded, needs to be in the introduction, since this article is the redirect for this term, and as the sources I listed above show, it is probably the most common name today for these devices.
  • The introduction should make clear that these are antique, obsolete devices.
  • The introduction should state that they used "crystalline minerals", as opposed to the manufactured semiconductor junctions used in modern diodes, to limit the definition to historical detectors.
  • "...Greenleaf Whittier Pickard discovered that two different materials in physical contact... would function as a detector..." The sources I've read seem to say that Karl Ferdinand Braun discovered this [17], [18], [19]. Since his time researchers have understood that "asymmetrical conduction" was a property of a contact between two substances, not a single substance.
  • The word "wireless" is ambiguous; it has been used twice in radio history. It was used around the turn of the century for the first primitive radio communication systems, which is how it is used in this article. But to modern readers, the term now means digital devices that are networked by radio; Wifi. Therefore to avoid misunderstanding I think it is better to use the word "radio" instead of "wireless" in historical articles like this. "Radio" is the correct modern translation of the obsolete historical term "wireless".

--ChetvornoTALK 09:48, 16 May 2018 (UTC)[reply]

Editor @Chetvorno:, Your suggestions do contribute to improving the article, after all the idea is to improve it. I have incorporated your suggestions, with the following possible caveats:
  • The crystal detector was used in radio measurement apparatus, like wavemeters, see Bucher Wireless Experimenters Manual, Chapter XI.
  • The terms 'antique' and 'obsolete' seem very POV. The article is unambiguously about historical technology, especially considering the hatnote.
Thank you, LSMFT (talk) 14:41, 17 May 2018 (UTC)[reply]
@LSMFT: I think the current lead is still too abstract for general readers: "A crystal detector is...a device that provides a physical contact between a crystalline mineral and a metal or between two minerals for the purpose of rectifying radio frequency alternating current so as to permit an indicator or headphone to produce a visible or audible output.".
This is an example of a common problem in Wikipedia technical articles; the lead definition gets expanded and generalized with marginal cases and technical exceptions until it becomes incomprehensible to ordinary readers. The use of crystal detectors in wavemeters is an interesting fact and should be in the article. But it doesn't change the definition of a crystal detector as a demodulator used in radio receivers to extract the information-bearing audio signal from the radio wave. A wavemeter is a radio receiver, a calibrated receiver used to tune up transmitters. And this was just a tiny specialized application; the vast majority of detectors were used in ordinary receivers for listening to radio stations.
I don't understand why you say "antique" or "obsolete" is POV. There are no cat whisker detectors being used in modern radios. There are still some being produced, but these are for educational purposes, or antique replicas; they're not being used in iPods or boom boxes.
Thanks, --ChetvornoTALK 17:35, 22 May 2018 (UTC)[reply]
Editor Chetvorno et al,
  • The intro is simplified now to state: "...so as to permit the radio program to be heard in the headphones." Hopefully that is more comprehensible to average readers.
  • A previous editor did include in the last paragraph of the history section the terms "obsolete" and "antique" in reference to crystal detectors; those terms remain in the article.
  • The function section now includes an explanatory sentence prior to the figure.
Thank you, LSMFT (talk) 16:08, 24 May 2018 (UTC)[reply]

Cat Whisker[edit]

Again - too many cooks spoil the stew. After reading the above section and the "back-and-forth", we now have a tiny section entitled "Cat Whisker" - which contains quite possibly the WORST description of a Cat's Whisker diode detector ever written.

The phrase: "... a springy piece of thin metal wire, forms the metal side of the junction ..." has NO meaning for the average reader, since the author has gone to some incredible lengths to avoid using the word "DIODE" - which is what a Cat Whisker is. It restricts the flow of electrons in one direction, and passes them in the other. By definition. The word "junction" has no specific meaning unless it is in the context of a diode. A junction could be anything. We're not talking about railroad tracks here.

So after all the discussion above, and all the votes back and forth, the end result is a short, poorly worded section entitled "Cat Whisker" - without, somehow, saying that a Cat Whisker is an early, cobbled-together, rudimentary form of diode that required "fiddling" to make it work properly. That's all it was. So why not just say that and avoid confusing people with partial and ambiguous descriptions? The reference(s) at the top of the article to Cat Whiskers are especially frustrating without a direct hyperlink to the definition, since virtually no one will have any idea what it is at that point so early on.

Further, the top of the page is supposed to be a brief overview of the topic. This one is all over the place. Is this the best we can do? The underlying key to this entire topic is DIODES, and that is the point that should be driven home, along with its relevance to Amplitude Modulation and rectification. Diodes.

Many people wrongly believe that the "crystal" part of early AM detectors was the earpiece, containing some type of piezoelectric transducer. It would be a good idea to clear that up here also.

Finally, the term "OBSOLETE" should be included when discussing Cat Whisker diode detectors. They are in fact, obsolete, and have been for many many decades. Can we not wedge that in somewhere for the sake of clarity? I'd hate for a young reader to think it was something they might want to try and build instead of just grabbing a 1N35 at Fry's or from the junk drawer. I always imagine my grandchildren reading an article like this - and then just walking away from the whole idea - because it is overly confusing. 98.194.39.86 (talk) 09:32, 13 June 2018 (UTC)[reply]

Did you know that a camel is a horse designed by a committee? 7&6=thirteen (☎) 15:16, 13 June 2018 (UTC)[reply]
I agree with most of these criticisms (although I was a major participant in the above Talk page discussion, I did almost none of the subsequent editing of the article). I just finished a complete rewrite of the introduction which explains better what crystal detectors do, includes the fact that they are "obsolete", and were the first semiconductor diodes. Other errors I corrected:
  • In the lead sentence, "a device...for the purpose of rectifying radio frequency alternating current..." gives the impression that the detector was a general purpose rectifier.
  • "...Greenleaf Whittier Pickard also observed that two different materials in physical contact, with no local power source in the circuit, would function as a detector..." is false, this was observed first by Braun and Bose.
  • "Crystal detectors of the configuration commonly referred to as the cat whisker detector type became very commonly used in crystal radios." Misleading: all crystal detectors were used solely in crystal radios.
  • "The crystal detector was an early predecessor of semiconductor diodes." False: the crystal detector was the first form of semiconductor diode.
What do you think? --ChetvornoTALK 05:19, 28 June 2018 (UTC)[reply]
I plan on rewriting the body of the article to correct some of the other problems you noted. --ChetvornoTALK 05:55, 28 June 2018 (UTC)[reply]
Editor Chetvorno, thank you for doing the re-writing. While I don't agree with every little choice of words, my opinion is that the article is continually improving. My opinion also is that 98.194.39.86 could contribute a lot to the following article: Donkey.
LSMFT (talk) 17:30, 29 June 2018 (UTC)[reply]
@LSMFT: I'm sorry, I was harsh above (IMHO so was 98.194.39.86|). There was nothing in the intro that was false. As you say, it was mainly a disagreement about wording. I respect your adherence to sources, and your collegial attitude. Thanks! --ChetvornoTALK 22:13, 3 July 2018 (UTC)[reply]

History section[edit]

Rewrote and expanded "History" section. I'm not quite done adding sources. --ChetvornoTALK 23:38, 9 August 2018 (UTC)[reply]

Awesome job, Chet! Thanks for taking this on. I made some superficial edits; hope that's all OK. Dicklyon (talk) 01:07, 10 August 2018 (UTC)[reply]
@Dicklyon: Thanks for the cleanup! There's a lot of other stuff in there that probably needs work. I left the citation template markup in expanded format with one field per line, which I know many editors object to; I'll get to that. --ChetvornoTALK 21:45, 24 August 2018 (UTC)[reply]
I prefer it as you did it. Dicklyon (talk) 03:08, 25 August 2018 (UTC)[reply]

It's sad to read this without seeing credit given to David Edward Hughes who single handedly invented Radio (and the crucial Detector) long before Hertz, Braun, etc.

It is true that recognition of Hughes is relatively recent, but since his papers and laboratory models have become available, there is now no doubt that he developed a working radio system, as well as various forms of Detector and Coherer.

Perhaps it would be useful if the editors of this article would read https://en.wikipedia.org/wiki/David_Edward_Hughes

It is also sad the the editors don't understand the interchangeability of the "rectifier" explanation of Detection, v/s the "Mixing" explanation of Detection. The first uses the Time Domain model, while the latter uses the Frequency domain. But they describe the same phenomena.

Gutta Percha (talk) 12:53, 27 August 2019 (UTC)[reply]

the wire whisker is the anode, and the crystal is the cathode[edit]

The article says: the wire whisker is the anode, and the crystal is the cathode. This obviously depends on whether the crystal is n or p type. It might be that some crystals tended one way, so that the rule applied. During WW2, silicon point-contact rectifiers were used with microwave radar at 3GHz and 10GHz. At one point after the war, someone had a Si crystal that was p-type on one end, and n-type on the other. That is, when used as a point contact rectifier, one end conducted one way, and the other end the other way. Understanding this effect led to the beginning of modern semiconductor device physics, including the point contact transistor and pn-junction diode. Gah4 (talk) 06:58, 4 January 2020 (UTC)[reply]

Cat Whisker Buzzer[edit]

The section "Cat Whisker" correctly identifies the "buzzer" used to aid in activating the detector, but is incorrectly linked to Buzzer rather than Spark-gap transmitter. The "buzzer" on early receivers was a spark-gap transmitter in miniature and was called a "buzzer" because it made an audible clicking and buzzing noise because the relay would open/close anywhere from 400 to 2,000 times per second. With each sparking at the relay contacts, a jolt of radio static was generated. When the operator could hear the static through the detector then he knew he had corrected . It is not at all related to the "beeper" or "buzzer" at Buzzer. This is not original research, please see attached schematic. When switch S1 closes current flows through coil BZ, which establishes a magnetized field, which opens it's relay contact, which interrupts the circuit and causes a spark across it's terminals. Because current has stopped, the magnetic field collapses, which returns the relay contacts to their Normally-Closed position, which causes a spark between the contacts and, since current may again flow through coil BZ, the cycle continues. Gnomenklatura (talk) 02:10, 21 February 2022 (UTC) [reply]

Alternate crystal detector materials.[edit]

A penny and a safety pin makes a good poor mans Crystal Detector. 2601:408:503:58F0:B586:B9D6:A66F:F354 (talk) 18:21, 23 February 2022 (UTC)[reply]

Bare bones.[edit]

A tuning system is not required, need only antenna (50 feet), ground rod, high imp earphone, Crystal Detector (penny and safety pin). You'll hear all the stations simultaneously but who cares ? One will usually overpower the rest significantly . 2601:408:503:58F0:B586:B9D6:A66F:F354 (talk) 18:33, 23 February 2022 (UTC)[reply]

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