Abstract: In a piezoelectric vibrator which has excitation electrodes respectively disposed on the top surface and undersurface of a piezoelectric substrate, at least one of the excitation electrodes being an inverted-mesa electrode that has a recess formed in the opposite side of the electrode from the side which contacts the piezoelectric substrate. Thus, an AT-cut quartz resonator in which the capacitance ratio .gamma. is reduced to a value below the limit value can be provided as a result of use of the inverted-mesa electrodes as excitation electrodes.

Abstract: For the purpose of utilizing the characteristic in a vibration energy entrapping mode of a higher order symmetric or asymmetric mode vibration generated when a piezoelectric resonator is excited, there are provided a portion having a cutoff frequency f.sub.2 about an energy entrapping portion having a cutoff frequency f.sub.1 for strongly exciting a higher order symmetric or asymmetric mode vibration and at least one energy absorbing portion having a cutoff frequency f.sub.3 (at least f.sub.1 and f.sub.3 <f.sub.2). The size of the energy entrapping portion (electrode), amount of plateback (f.sub.2 -f.sub.1)/f.sub.