A simple pre-stress estimating method of langevin transducers Bo, Fu Ting, Li Hemsel, Tobias capacitors impedance convertors piezoelectric transducers stress analysis Langevin transducers basic circuit theory capacitor impedance converter piezoelectric equation pre-stress estimating method voltmeter Capacitors Educational institutions Equations Force measurement Impedance measurement Manufacturing Mechatronics Piezoelectric transducers Voltage Voltmeters Langevin transducer capacitor piezoelectric element pre-stress A simple pre-stress estimate method of Langevin transducers is studied. The measurement setup consists of a capacitor, an impedance converter and a voltmeter. Based on the piezoelectric equation and the basic circuit theory, the mathematical expression between the pre-stress and the voltage across the capacitor is derived. The pre-stress level can then be calculated out of the measurement of the capacitor voltage. In order to evaluate the precision of this method, a force washer is used to measure the pre-stress of the Langevin transducer. The result shows the pre-stress level obtained from this method is 30-40\% higher than the pre-stress level measured by the force washer. This method is simple and can be used to estimate the pre-stress of various Langevin transducers. The precision of this method can be raised if d33 is identified under different pre-stress levels. 2008 info:eu-repo/semantics/conferenceObject doc-type:conferenceObject text http://purl.org/coar/resource_type/c_5794 https://ris.uni-paderborn.de/record/9568 Bo F, Ting L, Hemsel T. A simple pre-stress estimating method of langevin transducers. In: <i>Piezoelectricity, Acoustic Waves, and Device Applications, 2008. SPAWDA 2008. Symposium On</i>. ; 2008:324-327. doi:<a href="https://doi.org/10.1109/SPAWDA.2008.4775801">10.1109/SPAWDA.2008.4775801</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1109/SPAWDA.2008.4775801 info:eu-repo/semantics/closedAccess