| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a deterioration detector in which the degree of elongation/ contraction of a piezoelectric actuator can be grasped without fixing a sensor element externally, and deterioration of the piezoelectric actuator can be detected surely in the early stage. <P>SOLUTION: The deterioration detector comprises a piezoelectric actuator A, a DC controlled power supply S, a high frequency power supply H, a circuit for applying a high frequency voltage to the piezoelectric actuator from the high frequency power supply through a capacitor circuit, a circuit for measuring a signal voltage indicating the variation in the high frequency terminal voltage between a pair of electrodes 20 and 21 generated by variation in the capacitance of the piezoelectric actuator, and a comparison/alarm circuit delivering an alarm based on a measured voltage level wherein deterioration of a piezoelectric actuator under driving is detected by blocking DC currents by means of a capacitor in the high frequency voltage applying circuit so that subsequent high frequency circuit is not affected by the DC control power supply S. <P>COPYRIGHT: (C)2003,JPO |
