| 摘要 |
PURPOSE:To increase an output voltage through longer coil length while keeping the mass and area of board less, by providing a coil on both surfaces of the board. CONSTITUTION:Coils 12, 14 and 13, 15 are formed on front and back of coil supporting plates 6a and 6b. Terminals 13a and 14a are respectively formed at a position corresponding to the front and back of the supporting plates 6a and 6b, and both the terminals 13a and 14a are electrically connected via a through- hole 13b provided at the location of the terminals 13a and 14a at the coil supporting plate 6a (similarly at the coil supporting plate 6b). Thus, electric generation by the coil 13 which was conventionally given, plus that by the coil 14 at the back side can also effectively be used, allowing to increase the output voltage. Since the mass and area of the supporting plates 6a and 6b can not be increased, no deterioration in the sound quality and characteristics can be caused. Thus, the output voltage can be increased while keeping the mass and area of the board less. |
