Deriving an electrical model of a two terminal piezoelectric buzzer from its impedance response

Determining the model of a piezo element is essential in order to identify its characteristics that are suited to a particular piezo based application. Usually piezo elements are modelled using basic constitutive laws of piezo, but these models depend on specific vibrational mode(s) of the piezo element. Various types of electrical models are also available for the piezo, but most of these models simulate the frequency response of the piezo element near the resonance-antiresonance regions in terms of their voltage magnitudes. It is necessary to analyze the contributions of the individual blocks before proposing a model so that any required change can be predicted and accordingly the design can be modified. This paper proposes a systematic development of an electrical series model of a piezo buzzer by analyzing the various possible components of its experimental complex impedance response. This developed model suitably represents the overall complex behaviour of a typical piezo buzzer in the required frequency range, including its dominant vibration mode.