 Piezoelectric energy harvesting

Piezoelectric energy harvesting uses the coupling between mechanical deformation and electric polarization in a piezoelectric material. Electrodes collect charge displaced by changing strain, and an attached circuit can transfer some of the supplied mechanical energy to a load. The piezoelectricity is a conversion mechanism; it does not supply energy independently of the applied deformation.

A piezoelectric patch bonded to a bending beam is a simple apparatus. Periodic bending produces a varying voltage; connecting a load permits current and energy transfer. The output depends on strain, frequency, the element's capacitance and the load. A one-time static push can charge the element, but continuing power requires continuing mechanical input. Mechanical losses and electrical leakage limit the recoverable energy, and the electrical boundary condition can alter the beam's effective stiffness and damping.