| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio wrist watch capable of determining whether the illuminance of light radiated to a solar battery is high on basis of a plurality of different criteria without directly measuring an output voltage and an output current from the solar battery.SOLUTION: A radio wrist watch comprises: a solar battery; and an illuminance detection circuit for outputting a signal indicating whether an illuminance of light radiated on the solar battery exceeds a given threshold, the given threshold being switched over between a first illuminance threshold and a second illuminance threshold, the radio wrist watch being controlled to finish operating in a power saving state if the signal indicating that the illuminance exceeds the first illuminance threshold is output, and the radio wrist watch receiving a satellite signal containing time information from a satellite and displaying time in response to the time information contained in the received satellite signal if the signal indicating that the illuminance exceeds the second illuminance threshold is output. |
