Straight-forward arrangements of electric charges and elastic springs may be used to better
understand and to predict the electromechanical behaviour of various electro-active dielectric materials. The socalled
charge-spring model is essentially a macroscopic version of the microscopic Lorentz oscillator for
modelling the interaction between electrons and nucleus in an atom. The charge-spring model helps to easily
understand piezoelectric resonances in heterogeneous dielectrics and to predict the piezoelectric response in
various materials. In this contribution, the charge-spring model and the connections between its constitutive
elements and the relevant properties of established and newly designed piezoelectric materials will be briefly
reviewed. Furthermore, an extension of the model to pyroelectricity in the same or other similar heterogeneous
dielectrics will be attempted by introducing additional constitutive elements that represent for instance thermal
expansion, entropy-related polarisation, etc. and that are again related to macroscopic sample properties. With
such models, it should be possible to explain, to predict and to further optimise not only primary and secondary
piezoelectricity, but also secondary and primary pyroelectricity – with respect to direct and inverse transduction.