Piezoelectric Equations of State and Their Application to Thickness‐Vibration Transducers

The electromechanical equations of state are written in a number of forms, extending from Voigt's formulation to the recently introduced formulation with g and h as the piezoelectric constants. Those equations that are most appropriate in the theoretical treatment of the two chief types of crystal transducer are pointed out. A detailed treatment of the thickness‐vibration transducer is then given, leading to expressions for the electrical characteristics and for the acoustic vibrational amplitude and intensity. Some special cases are also considered.