IMPEDANCE AND FREQUENCY-CHARACTERISTICS OF ELECTRODE-SEPARATED PIEZOELECTRIC QUARTZ CRYSTALS IN LIQUIDS

The electrical equivalent circuit parameters of an electrode-separated piezoelectric quartz crystal (PQC), where the gaps between the electr odes and the crystal plate were filled with various liquids, were eval uated from admittance measurements and were compared with those of a n ormal PQC with Au electrodes adhering to the crystal plate. The resist ance parameter in the equivalent circuit of the electrode-separated PQ C was more sensitive to the specific conductivity, density and viscosi ty of liquids than was that of the normal PQC. This parameter, unlike that of the normal PQC, was also affecteded by the permittivity of the liquid. The effect of the liquid properties on the other parameters i n the equivalent circuit and the series resonant frequency are also di scussed.