The analysis of a passive damper employing smart materials is carried out through the description of a concept device loaded by a vibrating mass. Such a device is able to damp vibration and to produce electric energy (energy harvesting). Its basic properties are described in detail and the relationships between damping features and its physical parameters are shown. The analysis is carried out by a linear modeling at first, while the comparison to its actual behaviour is exploited to justify a more careful study where the material non-linearity is considered. Analytical results on the linear model and the spice numerical analysis of a non-linear model are presented.