Zaitsev Boris D, Semyonov Alexander P, Teplykh Andrey A, Borodina Irina A
Kotel'nikov Institute of Radio Engineering and Electronics of RAS, Saratov Branch, Saratov 410019, Russia.
Ultrasonics. 2022 Feb;119:106603. doi: 10.1016/j.ultras.2021.106603. Epub 2021 Oct 8.
The possibility of development a liquid sensor based on a piezoelectric resonator with radial concentric electrodes is shown. The specified resonator has a large number of resonance peaks corresponding to different vibrational modes. The influence of two types of liquid container with distilled water on the resonance characteristics of these vibrational modes is experimentally investigated. As a result, the optimal type of container and two vibrational modes with frequencies of 0.128 and 0.317 MHz were selected, which retain acceptable Q-factors in the presence of distilled water. The dependences of the resonance frequency and the maximum value of the real part of the electrical impedance of these resonance peaks on the conductivity of the liquid were measured. It has been found that with an increase in the conductivity of the liquid, the resonance frequency of the parallel resonance initially remains practically unchanged, but after reaching a certain value of the conductivity of water, it decreases for both resonances. In this case, the maximum value of the real part of the electrical impedance first decreases, reaches a minimum, and then increases in all cases. It is shown that using these dependences as calibration curves, one can unambiguously determine the conductivity of a liquid in the range of 45-5000 μS/cm.
展示了基于具有径向同心电极的压电谐振器开发液体传感器的可能性。所述谐振器具有大量对应于不同振动模式的共振峰。通过实验研究了两种装有蒸馏水的液体容器对这些振动模式共振特性的影响。结果，选择了最佳的容器类型以及频率为0.128和0.317MHz的两种振动模式，它们在存在蒸馏水的情况下保持可接受的品质因数。测量了这些共振峰的共振频率和电阻抗实部最大值随液体电导率的变化关系。已经发现，随着液体电导率的增加，并联共振的共振频率最初实际上保持不变，但在水的电导率达到一定值后，两种共振的频率都会降低。在这种情况下，电阻抗实部的最大值首先减小，达到最小值，然后在所有情况下都会增加。结果表明，利用这些变化关系作为校准曲线，可以明确确定45 - 5000μS/cm范围内液体的电导率。
