How does electron in a piezoelectric material flow to produce electricity? I read about piezoelectricity but I don't know exactly how it works. When stress is apply to piezoelectric material, the structure deform and create non-zero dipole moment and then what happen? How does electron flow? Does electron flow from higher electronegativity to lower electronegativity and why piezoelectric material must keep be deforming to produce electric current, can it just deform and keep it in that shape to produce constant electric current? So simply, I don't know how electron flow from where to where inside piezoelectric material. Thank you.