| 摘要 |
PROBLEM TO BE SOLVED: To extend the duration of a built-in secondary battery in a simple constitution by providing a radio communicating means which operates communication by setting a radio communication line with a prescribed station, secondary battery which supplies a power source to the radio communicating means, and generating means which supplies charging currents to the secondary battery. SOLUTION: A portable telephone set 10 incorporates a secondary battery 31 such as a lithium ion battery as a power source, the output voltage of the secondary battery 31 is adjusted by a power source circuit 32, and this is supplied as a power source for operation to each circuit such as a radio communicating means in the portable telephone set 10. A terminal 33 for charging is connected through a diode 34 for preventing back flow with this secondary battery 31, and when the portable telephone set 10 is connected with a charger, the secondary battery 31 is charged by charging currents supplied from this charger to the terminal 33. Then, a solar battery panel 35 is attached as a generating means to the portable telephone set 10, and the charging currents outputted from the solar battery panel 35 are charged through a diode 36 for preventing back flow to the secondary battery 31. |
