Klaas Robers wrote:The modern high frequency crystals vibrate in a "shift-mode". That is, if you lay the crystal flat on the table, that the top plane and the bottom plane move left-right-left with respect to each other. This gives only visible and feelable movement at the very thin left and right edges. The larger old crystals have much lower resonance frequencies, because the frequency is directly coupled to the dimensions of the crystal.
Hi Klaas thanks for the Informative reply that does make sense from what i have noticed very much so on the 2 mhz crystal where the liquid tends to gravitate to one of the edges .
At resonance there is an accoustic movement / standing wave in the crystal. In most cases the length / thickness is 1/2 wavelength of the accoustic wave in the crystal. Accoustic waves travel in crystal, but also in glass, with a speed of about 5 km/sec. So a crystal of 10 MHz carries a accoustic wave with a wave length of 10 000 (m/sec)/ 10 000 000 (MHz) = 1/1000 meter. You will see that the crystal has a thichness of 1/2 mm, i.e. the size of a half wavelenght. If you have a micrometer, measure the thickness of your 4.4 MHz crystal.! Then you can calculate the exact speed of sound in the quartz.
So there is a time delay via the crystal and also a speed delay depending on what liquid is used (density) if we are talking of it in the form of a jeffree cell very much a delay line happening , i don't have any thing to test the thickness of a crystal no way on a newer one , the larger ones coming perhaps .
Low frequency crystals are large. A 100 kHz crystal has (in this case) a length of 5 cm. Yes, it is as simple as that.
I think crystals of the same frequency a large older one and a newer small case type thickness would follow the large would still be thicker ..higher the frequency thinner the crystal the lower thicker it would be `,i am interested to see how thick the 8 mhz one's coming are ..will show them when they turn up .