I understand that the principle behind it is piezoelectricity and electrostriction (inverse piezoelectricity), but how does one make the crystal vibrate?
The only thing I can think of is using an alternative tension source, but wouldn't that make the crystal vibrate at the frequency of the source? Also, for example quartz wristwatches use a battery as a power source, which are DC.
From what I understand, it seems like it is sort of cyclical system where the where an initial tension create a strain via electrostriction, and that strain causes a piezoelectric effect which creates an electric field, which creates electrostriction... In that case, how would the battery help the system?