Practical applications of piezoelectric resonators with lateral electric field

The paper is devoted to the possibilities of the applications of piezoelectric resonators with lateral electric field for analysis of liquid properties and measurement of microdisplacements. It has been shown that the sensitivity of liquid sensors may be significantly increased by using the module of electrical impedance or admittance on the fixed frequency near the resonance as informative parameter. The change of pointed parameters may achieved 30% and 70% for the change in viscosity from 1 to 1000 mPa×s and for the change in conductivity in range 100 -10000 μS/cm. The second application is based on the fact that electric field of the resonator penetrates outside of piezoelectric plate. The experiments concerning with influence of the gap between free side of resonator and conductive and dielectric plate on the frequencies of series and parallel resonances were carried out. Obtained results have shown the possibility of development of meters of microdisplacements which may be used for permanent monitoring of deformations and crack opening of various constructions, elements of bridges and building, and also for measuring small displacements of two objects respectively each other. It has been demonstrated that the frequency of parallel resonance is unambiguously determined by the width gap in ranges 0 – 0.3 mm and 0 – 2.5 mm for conducting plate and plate of corundum, respectively. The frequency of series resonance does not depend on width of gap but is defined by the temperature. So the frequency of series resonance allows to determine the temperature and to perform the needed corrections.