A new approach to the development of quartz crystal sensors distinguishing between mass loading and liquid damping

Characteristic damping coefficient K/sub c/ is introduced to distinguish between the effects of mass loading and liquid damping of a quartz resonator vibrating in liquids. When the mass loading of the quartz resonator is constant the value of /spl kappa//sub c/ depends only on the parameters of the resonator itself and not on the properties of the attached mass or liquid. The effect of mass loading can be distinguished from that of liquid damping by measuring the frequency shift and the amplitude of the quartz resonator simultaneously. A series of experiments were carried out to test the value of /spl kappa//sub c/, and the influence of the resonator parameters on /spl kappa//sub c/ was studied, e.g., the electrode area, the harmonic number, and the fundamental frequency.