An alternative method for the measurement of the clamped capacitance of disk shaped piezoelectric ceramics

Several measurement methods for the dielectric permittivity at constant strain ε33S of a piezoelectric ceramic have been proposed1-2. In this paper a comparison of these methods is made and an alternative and complementary method is proposed. This method requires a clear and well shaped thickness resonance and is based on the measurement of the electrical input impedance at the frequencies fs and fp of the fundamental resonance of the thickness extensional mode of vibration. Other parameters - kt and Qm - can also be obtained from these measurements1-3.Several samples of different piezoelectric ceramics have been measured and the results using the proposed and the above mentioned methods are compared.