| 摘要 |
PURPOSE:To optimize designing conditions, by boosting voltage level of an analog signal, and containing a transformer which drives a piezoelectric speaker into a columnar ferrite core of below 7mm. in outer diameter. CONSTITUTION:Transformer 401, 402 are choked magnetically and contained in a columnar ferrite core to lessen flux leak as possible. In this case, from the view- point of boosting capability, the bigger core is the better. However, a practical value for transformer diameter is limited within 7mm. because of the limitation to thin the overall thickness of a wrist watch. The battery diameter is also limited, and the winding ratio must be set at a value over 10 times to decrease peak values of frequencies. |
