Question about crystal used on watch

[Willen]

I think all the general analogue and digital hand watch, table watch has a small crystal like small electrolytic capacitor. Is it really crystal? If YES, what is the frequency of these crystal used on watch? I should have to know the friquency of these crystals, help me!

 

[MrAl]

Hi,

It is a crystal, and the frequency is probably 32768Hz. Someone else might have more specific information though.

 

[alec_t]

....and the crystal material is quartz.

 

[Willen]

Can I use it as a replacement of 38KHz crystal? (in NJM2035 based stereo encoder) in here www.electronics-diy.com/stereo_encoder.php Please

 

[WTP Pepper]

Can I use it as a replacement of 38KHz crystal? (in NJM2035 based stereo encoder) in here www.electronics-diy.com/stereo_encoder.php Please

I guess not. Crystals are used because of their inherant stability and if something is specified at a frequency then changing it generally will cause all sorts of odd problems (clocks running fast/slow etc).

Watch crystals are usually optimised for maximum stability at body temperature (as that's where they will spend most of their time glued to the wrist).

 

[cr0sh]

...and here I was thinking this might be some strange thread about the clear front of a watch (also called a "crystal", at least, back in the "old days")...lol.

 

[kubeek]

Can I use it as a replacement of 38KHz crystal? (in NJM2035 based stereo encoder) in here www.electronics-diy.com/stereo_encoder.php Please

I guess the input signals would be then low-passed at 16KHz, but the also might overlap in the narrower band. Also, you wouldn´t be able to decode the joint stereo back into separate channels without the same freqeuncy decoder, even though the sound coming out of a 32-38khz encoder-decoder combination might be very interesting
Edit: or mabye not, since this uses time-division multiplexing and the decoder will fall back to mono mode if it doesn´t receive the 19khz carrier.

 

[crutschow]

Can I use it as a replacement of 38KHz crystal? (in NJM2035 based stereo encoder) in here www.electronics-diy.com/stereo_encoder.php Please

You could but then it wouldn't properly decode the FM stereo signal which has a subcarrier of 38KHz.

 

[RCinFLA]

The crystals for watches and clocks are 32.768 KHz since the oscillator can be divided down with a simple series string binary ripple counter to produce 1 pulse per second.

https://www.ecliptek.com/crystals/e3wc/

There are 32.000 KHz crystals of similar configuration. You need to match the load capacitance which sets the center frequency. There are load capacitance specs from 6 pF to 32pF with 10 pF being the most common. The lower the load capacitance spec the lower the oscillator current will be since the CMOS drivers draw less current the lower their load capacitance is.

 

[Willen]

=WTP Pepper;1061952changing it generally will cause all sorts of odd problems (clocks running fast/slow etc).

Can I run analogue clocks to backward or anti-clockwise by general modification? It will be interesting ha ha!

 

[Willen]

you wouldn´t be able to decode the joint stereo back into separate channels without the same freqeuncy decoder, even though the sound coming out of a 32-38khz encoder-decoder combination might be very interesting
Edit: or mabye not, since this uses time-division multiplexing and the decoder will fall back to mono mode if it doesn´t receive the 19khz carrier.

-It is difficult to find 38KHz X in my market. Which another general (common) device uses this 38KHz crystal?
-What will happen if I connect 2 crystals in series and parallel?

 

[Diver300]

If you put two crystals in series or parallel, the circuit will run at the frequency of one of crystals, or not run at all. Crystals behave as tiny capacitors unless the frequency at their resonant frequency.

38 kHz crystals are quite rare. Tuning fork crystals can be made at any frequency from about 20 kHz - 300 kHz but they are usually only made at 32768 Hz.

It might be possible to generate a 38 kHz waveform with a divider or a PLL, and to drive either the "crystal" or the "capacitor" connection on the NJM2035

This thread talks about connecting an external oscillator to a BA1404, which is similar:-
**broken link removed**

 

[Diver300]

Digikey seem to stock them.

https://www.digikey.co.uk/product-detail/en/ABS25-38.000KHZ-T/535-10243-1-ND/2218056