Because some of small applliance( e.g: light, heater and so on ) can use two way electricity in Japan. One is atomic energy. One is 太陽能. When some happens seem to 11 March. Many family cannot change their electricity from atomic energy to 太陽能. Because the 轉換器 use atomic energy , when atomic energy stop and then the轉換器cannot work. Some 轉換器use battery, but it just keep one hour only.