This paper introduces an electromechanical model suitable for most piezoelectric devices, including the piezoelectric bimorph beams. The model provides an improved approach to design and to analyze the performance of piezoelectric transducers, especially in the case where piezoelectric devices are embedded in compound electronic systems. The main objectives of this work are: (i) to develop a versatile and easy-to-use electromechanical model of a piezoelectric transducer. The proposed model is based on the physical properties of the device and can be easily adapted to different operating conditions using experimental data analysis; (ii) to introduce an approach based on scattering (S-)parameters for better characterizing the frequency response of systems that exhibit resonant phenomena. To our knowledge, this is the first time that this approach has been applied to electromechanical transducers; (iii) to show the functionality of the model on a specific application. Results prove that although the model does not take into account second order effects such as nonlinear behavior and hysteresis, it fairly fits experimental data so as to be used for proposing and precisely describing new applications of piezoelectric sensors and actuators.