| 摘要 |
PURPOSE:To stabilize feedback voltage to the temperature change of a stator by connecting electrostatic capacity in parallel with an electrode 1 for feedback. CONSTITUTION:In a driving circuit for an ultrasonic motor, feedback voltage is lowered by a rheostat VR1, rectified and smoothed by a diode D and a capacitor C1 and changed into DC voltage, and input to an operational amplifier OP. A capacitor Ca for stabilization is connected to the feedback voltage input section of a drive power circuit at that time. Accordingly, the variation of capacitance with the modification of cable length with regard to an electrode 1 is small, the variation of feedback voltage can be reduced remarkably, and the circuit is hardly affected, thus easily changing the length of a cable. |
