| 摘要 |
PURPOSE:To prevent overcharging of solar batteries and enhance safety by providing a photo oscillating element and a counter which counts the outputs thereof and stopping charging for a fixed time after charging of a fixed quantity of light when fixed quantity of light has been charged. CONSTITUTION:A photo oscillating element 5 is provided on the dial or other of a solar battery watch. When light enters the photo oscilating element 5 and solar battery 8, charging is started and the oscillation frequencies of the photo oscillating element 5 are counted in a counter 11 according to the illuminance of the ambinent. When the count value of the counter 11 reaches a certain predetermined value, the output signal is delivered to a switch circuit 9, by which the switch circuit is opened so that the electromotive force of the solar battery 8 will not charge the battery. The reset signal of the counter 11 is produced by the output of a frequency divider 12 and after lapse of a fixed period the switch circuit 9 closes, causing the charging to be started again. |
