| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-reliability driver whose electromechanical converter element is not damaged, even if an excessive reverse voltage is generated. SOLUTION: Between a driving power source PS and the ground, a series circuit of a first constant-current circuit 141 and a first short-circuiting circuit 142, and a series circuit of a second constant-current circuit 143 and a second short-circuiting circuit 144 are connected. Moreover, the positive electrode of the electromechanical converter 26 is connected to the junction (c) between the first circuit 141 and the short-circuiting circuit 142, and the negative electrode is connected to the junction (d) between the second circuit 143 and the short-circuiting circuit 144. Between the junction (d) and the ground, a protective circuit 146 composed of a limiting circuit comprising a bipolar transistor Tr3 is connected. |
