Hello,

i was wondering if someone can explain to me how the quartz worked, i made some research but all the information that i have was a little bit complicated to understand.
I want to know for example what is the difference between quartz 12Mhz 16pF and quartz 12Mhz 12pF?
I know the capacitor are diffrent but what could be the impact on a circuit if i choose one of these ?

thank you for your help

 

hi A91,
Welcome to AAC.
This simple video may help you understand.

E

 

Thank you very much i will look at it

 

Since your question was about the "load" capacitors, these two links are more directed at that specific question:

https://community.nxp.com/thread/388856 (simple calculations)
https://www.nxp.com/docs/en/application-note/AN3208.pdf (more calculations)

This is more general theory:
http://www.ti.com/lit/an/swra372c/swra372c.pdf

 

A quartz crystal has two resonant frequencies at or near it fundamental frequency. One frequency is the series resonant frequency and the other is the parallel resonant frequency. The value(s) of the external components are selected to encourage the selection of one of those frequencies. You can also design your circuit to favor oscillation at the odd harmonics of the fundamental frequency. these would be the third, fifth, seventh, and ninth. I don't know of many designs using higher harmonics.