Power Output and Dissipation of a Negative Capacitance Shunt Coupled to Piezoelectric Transducers

A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control vibrations of flexural bodies. The electrical impedance of the negative capacitance shunt modifies the effective modulus of the piezoelectric element to reduce the stiffness and increase the damping which causes a decrease in amplitude of the vibrating structure to which the elements are bonded. The negative capacitance circuit is built around a single operational amplifier using passive circuit elements. To gain insight into the electromechanical coupling, the power consumption of the op-amp and the power dissipated in the resistive element are measured. The power output of the op-amp increases for increasing control gain of the negative capacitance. The power characteristics of the shunt are compared to the reactive input power analysis developed in earlier work.