| 摘要 |
<p>An electro-acoustic transducer (e.g. for use as a microphone in telephone systems) has a transducer plate (1) clamped at its periphery and having a piezoelectric layer (2). In order to reduce the increase in sensitivity which would otherwise be caused by the fourth harmonic resonance of the plate, the piezoelectric layer (2) is so dimensioned that, in use, the circular node which is characteristic of the fourth harmonic lies within the piezoelectric layer. <IMAGE></p> |
