| 摘要 |
PURPOSE:To reduce the number of parts in an electronic wrist watch by functioning the speaker drive circuit as a liquid crystal illuminating electroluminescent drive step-up circuit. CONSTITUTION:An electroluminescence 1 inserted as a reflecting plate of a liquid crystal is connected through a switch 2 to the secondary winding 5 of a drive step-up transformer of a piezo-electric buzzer 3. When the electroluminescence 1 is driven by higher than 20kHz, the buzzer 3 and the electroluminescence 1 can be selected by the drive frequency. |
