| 摘要 |
PURPOSE:To display the residual and charge capacities of a secondary battery at any time by using as the secondary battery a lithium battery, which has its voltage proportional to the capacity, so that the capacity may be digitally displaced in accordance with the detected value of the battery voltage. CONSTITUTION:The capacity of a lithium battery 13 of such a secondary battery for a watch as is charged by a galium-arsenide solar cell 11 is proportional to the voltage. This voltage of the battery 13 is detected by a battery voltage detecting circuit 14 so that the gate which is selected by the switch 15 of a display switching circuit 8 and by a switch circuit 16 is turned off during the term corresponding to the detected voltage level. As a result, the frequency divided output for the time display is fed to a driver 9 so that the capacity of the battery proportional to the battery voltage is digitally displayed in a time display element 10. Thus, it is possible to display the residual and charge capacities of the secondary battery at any time. |
