Stevekir

On 6/16/2011 at 9:16 PM, swansont said:

Yes you can make it vibrate; what you want to do is have an amplifier circuit with feedback, where the potential across the crystal is part of a capacitor, so the RC circuit has a resonance. That way you can tune the resistor (or a second capacitor) so that the voltage oscillates at the same frequency as the crystal. There are a lot of different circuit designs that will do this.

 

I have no problem with tuning the RC circuit to the frequency of the crystal. But how is it that the crystal used vibrates at the fixed speed of 32,768 vibrstions/sec. Is this number decided by nature? If so it is a remarkable coincidence that Providence has provided a number capable of being divided by 2  15 times  (or any other suitable number to replace the 15) to give a pulse of once per second. There is an infinite range of numbers in the world (such as 32,769 to (2 x 32,768-1)) that would not give this exact result and if Nature had "chosen" one of these, a quartz crystal could not be used.

Could the answer be that by manufacturing the crystals (by the million), they could be tested for the few that had the correct property? A time-consuming task.

What's the answer to this conundrum please?

Thanks.