| 摘要 |
PROBLEM TO BE SOLVED: To simplify a constitution of a charger by displaying a charging state based on a detecting result of a charging detection part. SOLUTION: A charger 7 detects the existence of loading to a telephone set 1, and a control part 12 controls a charging circuit 8 to start charging to a secondary battery 2. A voltage detection part 10 always monitors the voltage varying part of a charging line 7a to inform a control part 12 of it, and the control part 12 judges the charging state of the secondary battery 2 by the voltage varying part of the charging line 7a and continues charging it becomes full. The telephone set 1 makes a display control part 4 to judge the existence of charging depending on the result of monitoring the voltage varying part of a charged power source inputted to a charging input terminal 6 by a charging detection part 3. At the time of the presence of charging, a display part 5 displays the presence of charging to unnecessitate the providing of a display function for the charger 7 to simplify the constitution of the charger 7. |
