A continuous motional series resonant frequency monitoring circuit and a new method of determining Butterworth-Van Dyke parameters of a quartz crystal microbalance in fluid media

A new electronic design for continuous monitoring of the motional series resonant frequency of a quartz crystal microbalance either in vacuum or in single-face contact with a fluid medium is presented. The motional resistance is directly measured and a simple method for measuring L and C parameters of the Butterworth-Van Dyke equivalent circuit is described. The results are in agreement with impedance analyzer measurements. (C) 2000 American Institute of Physics. [S0034-6748(00)04806-1].