Tokio Kitahara

Characterization of Piezoelectric Lead Zirconate Titanate from the Viewpoint of Transducer and Power Generator Properties

Mechanical, electrical and transducer properties of piezoelectrics are estimated using a newly proposed method. Transducer properties of piezoelectrics, i.e., power generation and energy conversion properties, are useful for application to power microelectromechanical system (MEMS) devices. Electrical and mechanical properties of piezoelectrics could be estimated from the viewpoint of application to electronic devices using a trial measuring apparatus. The electromechanical coupling constant is estimated to be 0.53 in the case of lead zirconate titanate (PZT) using the same apparatus under short- and open-circuit conditions. The electromechanical coupling constant is calculated from the mechanical properties, i.e., two kinds of Youngs modulus. On the other hand, the output peak power of PZT transducers is determined to be approximately 3 µW, which is the product of a 1.8 V voltage and a 1.7 µA current, in the case of 40 N input applied load. Since output voltage and current exhibit linear relationships with applied load, the output electrical power is equal to the square of the applied load. This shows that piezoelectrics attached to the sole could realize mW electrical power through the efficient use of total human weight.

Piezoelectric transducer properties and its application to the micro power generator

This paper reports a newly proposal on the estimation method for piezoelectric transducer properties i.e. power generator and energy conversion ones in application for power MEMS devices. Electrical and mechanical properties of piezoelectrics could be estimated for the mobile electric devices with measuring apparatus built as a trial. The output peak power of PZT transducer is obtained to be 3 w W, which consists of 1.8 V in voltage and 1.7 w A in current, in case of 40 N input applied load. Since output voltage and current have linear relationships with applied load, the output electrical power is equal to the square of the applied load. On the other hand, the electro-mechanical coupling constant is estimated to be 0.53 in case of PZT in use of the same apparatus in short and open circuit conditions. It is possible to extract mW power in the equipment of piezoelectric transducers attached to the sole of the shoe, where human total weight is applied most efficiently. This mW output power is enough for actuation of the mobile electric devices.