| 摘要 |
PURPOSE:To obtain a change characteristic which is excellent in linearity and has less hysteresis by connecting an integral circuit to the first electrode of an piezoelectric element, and controlling the potential of the second electrode of the piezoelectric element so that the signal outputted from the integral circuit becomes a predetermined magnitude. CONSTITUTION:A piezoelectric element 4 is provided which consists of a piezoelectric material, a first electrode 6 for applying an electric field to the material and a second electrode 5, an integral circuit consisting of at least an operational amplifier 1 and a capacitor 2 is connected to the first electrode 6 of the piezoelectric element 4, and a means 3 is provided which controls the potential of the second electrode 5 of the piezoelectric element so that the signal outputted from the integral circuit becomes a predetermined magnitude. From the integral circuit, a signal depending on the charge Q stored between the electrodes of the piezoelectric element 4, and this signal is inputted to the control section 3 to determine the potential of the second electrode 5 so that a certain predetermined charge is stored. Accordingly, control of the piezoelectric element 4 by the charge Q is enabled. so an arbitrary charge can be provided to the piezoelectric element and maintained.
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