| 摘要 |
PURPOSE:To eliminate the battery change with utmost conservation of charged power by a method wherein a timer is operated according to an illumination intensity detection signal and subsequently, the time display is stopped after the expiration of the set time when an incident light is not obtained. CONSTITUTION:When there is no incident light, the output of an illumination intensity detecting circuit 30 inverts to 0 to turn OFF an AND gate 29 while a timer 31 starts. If the set time expires with no incident light, an RS type flip flop 32 is set through the timer 31 to turn OFF an AND gate 27 by a Q' output and the driving of a pulse motor 19 is halted through a signal switching circuit 22 to stop the time display while only the memorization of the results of time counting is done to an increment/decrement counter 23. This can hold back the power consumption by a solar cell 11 and a charger 10 to the minimum necessary level thereby eliminating the battery change through such a utmost preservation of the charged power. |
