title: Note: Piezoelectric strain voltage sensing at ultra-low frequencies.
abstract: Piezoelectric sensors have emerged as a versatile tool for measurement of various quantities such as pressure, acceleration, strain, or force across many industrial applications. When mechanically strained, electric charges are produced inside a piezoelectric transducer. These charges result in an electric field that may be measured as a voltage difference between two electrodes, from which the strain can be inferred. To measure this voltage the sensor must be interfaced with an external device that would typically have a finite input impedance. This, together with the capacitive nature of the piezoelectric sensor, results in an inability to measure strain at low frequencies. We propose a method, based on using a varactor diode in an oscillator circuit, which can result in accurate measurements of the piezoelectric voltage at ultra-low frequencies. We demonstrate successful measurements at 1 mHz.
authors: School of Electrical Engineering and Computer Science, The University of Newcastle, Callaghan, NSW, Australia. a.laskovski@gmail.com
authors: A
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authors: Laskovski
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authors: Moheimani
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authors: Yuce