The current paper presents a unified lumped parameter modeling approach for deriving generic analytical system models of reciprocal electromechanical (mechatronic) transducers for various physical working principles (e.g. electrostatic, piezoelectric, electromagnetic, electrodynamic). Starting from constitutive physical relations representing natural laws, the model hierarchy comprises energy based nonlinear EULER-LAGRANGE behavior models, linearized electromechanical two-port models forming constitutive transducer equations and MIMO transfer function models describing the causality based signal flow behavior to be used for control system design and analysis purposes. It is shown that the models describe in a generic way the unified behavior of reciprocal transducers under different operating conditions, e.g. voltage vs. current control. Moreover the models allow in a straightforward way the generic discussion, i.e. independent from the concrete physical working principle, of important transducer operational concepts such as impedance feedback or self-sensing.