| 摘要 |
PURPOSE:To provide the multi-functional telephone set in which low power consumption is realized through jointly using a solar battery. CONSTITUTION:Electric equipment sections such as an internal telephone set circuit 6 and a display circuit 14 or the like are activated through the reception of a station voltage Vc and a local voltage Vb, the telephone set is provided with a solar battery 19, a power changeover switch 20 selecting either an output voltage Va of the solar battery 19 or a sum voltage Ve obtd. by adding a station voltage Vc and a local voltage Vb to the output voltage Va of the solar battery 19, a voltage comparator 21 comparing the output voltage Va with a reference voltage Vd being a minimum operating voltage of the electric equipment sections, and with a control section 5 sending a switching signal to a power supply changeover switch 20 to select the output voltage Va when the output voltage Va is higher than the reference voltage Vd and to select the summing voltage Ve when the output voltage Va is lower than the reference voltage Vd based on the comparing result of the comparator 21. |
