Vibration Control of Piezoelectric Lead Zirconate Titanate Ceramics Using Negative Capacitance

We report on the results of an experiment on the damped vibration process of a lead zirconate titanate (PZT) Bimorph connected to a negative-capacitance circuit (NCC), which acts as a capacitor with negative capacitance. NCCs are of two types: a Soft NCC that softens the piezoelectric material, and a hard NCC that hardens the piezoelectric material. It was found that the amplitude and the damping time constant of the damped vibration of PZT ceramics connected to a hard NCC change markedly compared with those of PZT ceramics not connected to a hard NCC. In particular, the damping time constant becomes very small. The result suggests that the PZT ceramics become very viscous when connected to a hard NCC.