[time-nuts] quartz clock/watch question

iovane at inwind.it iovane at inwind.it
Sat Apr 19 08:19:57 EDT 2014


For digital clocks with analog hands, a 1sec pulse is easily detected by an 
electric guitar pick-up. The pulse is the one fed to the stepping motor. I 
noticed this while playing (I wear the watch on my right arm). Antonio I8IOV

>Da: n1hac at dartmouth.edu
>Data: 19/04/2014 6.00
>
>I have done that as well.  The G-Shocks have a trimmer cap (I have a 
>DW-6900/module 3230).  I don't remember the frequency at the adjustment 
>test point but it is something like 100 Hz.
>
>David
>
>
>On 4/18/14 7:40 PM, Jim Palfreyman wrote:
>> I've opened up my Casio G-Shock watch, found an electrical point, put an
>> oscilloscope on it and successfully adjusted it. From memory the frequency
>> was something weird, but I still tuned it successfully to within about a
>> second a month. I even think I posted to time-nuts on this...
>>
>> Jim Palfreyman
>>
>>
>>
>> On 19 April 2014 09:25, Bob Albert <bob91343 at yahoo.com> wrote:
>>
>>> I have tried to pick up the oscillator from my wristwatch and have been
>>> unsuccessful.
>>>
>>>
>>> I tried both magnetic and electric probes.  Nothing.
>>>
>>> Bob
>>>
>>> On Friday, April 18, 2014 4:12 PM, Tom Van Baak <tvb at LeapSecond.com>
>>> wrote:
>>>
>>>> When a quartz watch or clock is assembled, what method is used to get it
>>> as accurate as possible?
>>>
>>> Bob,
>>>
>>> First generation quartz watches had a tiny F/S (fast/slow) trimmer
>>> capacitor. These days it's done with skip cycles and one-time factory
>>> calibration. Think leap days or leap seconds -- it's easier and more
>>> reliable than changing the frequency of the oscillator itself. It's also
>>> one less part, easier to calibrate, and unlike active and passive
>>> components, math has no environmental sensitivity.
>>>
>>> Have a quick read of 32 kHz watch IC's like:
>>> http://www.nxp.com/documents/data_sheet/PCA2000_2001.pdf
>>>
>>> /tvb





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