Talk:Quartz clock

Page Title/Subject

I think these could all be merged: Timing crystal, Quartz oscillator, Crystal oscillator. If no one objects, I will put them all under Crystal oscillator. And maybe Quartz clock, also. - Omegatron 20:14, May 4, 2004 (UTC)

I guess quartz clock and crystal oscillator should be separate articles. One is a specific application of the other. I will move some material from each to the other, though. - Omegatron 15:16, May 7, 2004 (UTC)

Should it be mentioned that some quartz clocks are in fact user-adjustable in terms of frequency in a similar way to mechanical clocks? For example, I have a Casio W-780 (eletronic module 549) made around 1986 witch features a small screw that adjusts a variable capacitor in series with the crystal. This allows frequency adjustement and timing within 1 second per month for a good adjustement. -- rnbc December 25 2005

I have to ask - how on earth do you know how to adjust it, though? Do you have to wait a month and then see if you need to turn it a quarter screw counter-clockwise, or a half screw clockwise??? I do understand that there are many many applications where great accuracy are vital, and that there is something cool about having the most accurate watch possible, even if it will never make a difference in whether you are on time for meetings or when meeting your girlfriend for dinner. Just curious. -Fitzhugh 04:36, 1 September 2006 (UTC)

Well... basically you wait a week or so, until you have the perception where it's drifting, and slightly bump the screw in the right direction. In fact a 90 degrees adjustment is more like 10 seconds a month. My question is if the existence of such mechanisms should be mentioned, not if they are practical. Well, they work, and keep working in 2006, since the watch is still in good shape. Has not been adjusted in a few years and still drifts less than a second per month. At this magnitude the drifting is more temperature-related than really a drifting and can't be corrected, as far as I can see. This is just a curiousity, I think. I never saw another quartz watch featuring an adjustment screw. --Rnbc 18:34, 30 December 2006 (UTC)

Please explain the concept of "rating" mentioned under heading "Accuracy"

I'm afraid I just don't get what is meant by "rating" (as in "self rating")... clocks that compare their current time against an epoch or whatever. Funny, cause I'm usually very good at picking up concepts from context and have a decent education and understanding of how things work. I'd really like to learn what is meant here, so if someone knows, please explain! Maybe I'm just misreading it and it makes perfect sense to all others, I don't know. Thank you! -Fitzhugh 04:31, 1 September 2006 (UTC)

I think whoever wrote those paragraphs was confused and they just meant "regulating". I'm amazed that they have been there for so long without some knowledgeable editor sorting out the confusion. Only clocks that pick up the long-wave time signal can be self-regulating. Dbfirs 18:10, 31 March 2010 (UTC)

From what I understood (and I had to re-read it), the clock scales its own vibrations (which are generally a bit fast or slow) to how much time has actually elapsed between factory and recent set-point. For example, if the difference of the time you last set it to and the factory time is 2 years and 3 seconds, but the clock's vibration count tells it it has clocked 2 yr 14 sec, it will calculate the ratio between them (=1.0000002) and in the future compensate accordingly, now enlightened to its fastness or slowness. jellyturtle (talk) 23:41, 11 April 2010 (UTC)

History

There is an article in the Feb/Mar issue of History magazine ("The Timeless Appeal of Clocks") that states that Warren A. Marrison developed the first quartz clock, which is in agreement with this article. It states that this happened in New York, though. This is most likely correct since Bell Labs was New York based (city or state?) until the 40's, according to the wikipedia article on same. AFAIK Bell Labs has never been here in Canada (not the same as BNR Bell Northern Research). Does somebody have more info on Marrison? A search for him is how I got to this page.216.210.101.131 14:12, 13 April 2007 (UTC)

I think you're right. I put the location in as Canada because I had read it in some reference, even though I had never heard of Bell Labs research facilities in Canada. I can't find the reference now, so I've taken out the word Canada until I can nail down the location. Thanks. --Chetvorno^TALK 22:07, 27 February 2008 (UTC)

Link

You should link to Crystal_oscillator. 83.181.84.3 19:32, 3 May 2007 (UTC)

Accuracy

In the article it is written: "Standard-quality resonators of this type are warranted to have a long-term accuracy of about 6 parts per million at 31 °C: that is, a typical quartz wristwatch will gain or lose less than a half second per day at body temperature. If a quartz wristwatch is "rated" by measuring it against an atomic clock's time broadcast, and the wristwatch is worn on one's body to keep its temperature constant, then the corrected time will easily be accurate within 10 seconds per year". I'm a bit puzzled on how half a second per day would eventually add up to 10 seconds a year ... Am i missing something, or someone has lost an order of magnitude in the calculation? jonosphere (talk) 19:40, 12 March 2008 (UTC)

The next best thing to a clock that keeps good time is one that has a very predictable error. I think what this was trying to say is that you can *measure* the drift of the wristwatch, and since it can be measured and predicted, you can then correct its reading, with a result that's within 10 seconds a year. If I know my watch gains exactly 17 minutes a week, and I just deduct 17 minutes for every week since I last checked it against WWV, then I don't much care that it's otherwise a lousy watch, as long as its bad behavior is predictable. *Somewhere* I read about a cluster of cheap watches that, when cross-correlated and corrected for their various secular trends, produced a time standard that would otherwise have needed an atomic clock to realize. Is there a metrologist in the house? --Wtshymanski (talk) 01:43, 31 March 2010 (UTC)

The sentence doesn't make sense to me either. What is this "rated" concept? All except the very cheapest watches are calibrated before sale to obtain the best accuracy with that particular crystal. I still think that this sentence should be removed unless you can find a reference. The whole point about cheap watches is that the oscillators are not stable, so will not in general continue to keep correct time (though occasionally you might find one that does). A good quality quartz watch will keep accurate to within ten seconds a year without any maintenance and without "keeping it warm"! I recommend that we replace the dubious sentence with mine (which Wtshymanski reverted), or remove it altogether. Dbfirs 07:05, 31 March 2010 (UTC)

A few minutes' work with Google Books under "rating chronometers" will provide suitable references and I'll try to get one ot two. The concept is deeper than just checking the watch against the time beep. It's valid and illustrates what is (evidently) a less-well-known concept of timekeeping. Please don't delete the paragraph in question, it's useful to the encyclopedia. The best thing about Wikipedia is when you get to say "I never heard of *THAT*". --Wtshymanski (talk) 13:10, 31 March 2010 (UTC)

Hmm. Marine chronometer should have had a discussion of this, but mentions nothing after observing the time ball drop in the harbor. And Chronometry is a stub. Horology goes into clocks-as-collectible-objects more than it talks about actually using clocks to accurately measure time. More research is needed! --Wtshymanski (talk) 14:07, 31 March 2010 (UTC)

I'm always willing to learn, but the paragraph just doesn't ring true to me. I think that you are confusing "rating" with "regulating", but I'll give you time to come up with a reference. I agree that our aim is to build a better encyclopaedia, so thanks for discussing the matter. Dbfirs 14:09, 31 March 2010 (UTC)

Perhaps I am. I'm not a subject matter expert here. It seems to me that there's two different processes. In the first, you make a clock that keeps time as best you can make it, comparing to, say, astronomical observations. In the second process, you study how the clock varies with temperature and time and use that to correct the time readings made on the clock. Is the first process "regulating" and the second "rating"? If you look at the Google on-line copy of Bowditch's "American Practical Navigator", you'll find a discussion of marine chronometers are rated and the application of the corrected chronometer readings to navigation. While this is getting a little far afield from the observation about cheap quartz watches, the neglect of this topic on the Wikipedia makes me think we should not lightly discard this sentence. I wonder if the original contributor is still around and can expand on this? --Wtshymanski (talk) 16:28, 2 April 2010 (UTC)

User:Omegatron contributed a great deal on rating clocks back in May 2005; wonder if that user could point us at some good references? --Wtshymanski (talk) 16:42, 2 April 2010 (UTC)

Yes, it would be useful to have an expert on the subject. If I correctly understand the process, quartz crystals are cut to vibrate at a frequency slightly faster than 32,768 Hz, then the crystal is "rated" by comparing its frequency with a standard (e.g. Greenwich time signal or atomic clock), and the regulatory circuitry is adjusted to omit cycles so that the watch or clock keeps exact time. A good-quality crystal will then remain accurate to within about ten seconds a year, especially if the circuitry also has some temperature compensation built in. A lower quality crystal will not maintain its stability and will change its frequency at random, or as a result of mild shocks in use. My first quartz watch (in the early 1970s) cost me several weeks' pay, but it maintained this accuracy for many years until I accidentally threw it across the room, after which I had to regulate it using the adjuster inside the back cover. I would be interested to learn about self-regulating clocks if you happen to find a good reference. Dbfirs 18:30, 2 April 2010 (UTC)

(outdent) I've got the wrong user listed above - that was just a revert. Most of the text came in 2004; given the half-life of contributors, I think it's unlikely the original contributors are still around. Perhaps the Wikiproject listed above has someone who can explain this. --Wtshymanski (talk) 21:27, 2 April 2010 (UTC)