| 摘要 |
PURPOSE:To save a power in an apparatus which is unnecessary to electrify at night, by cutting off a power source automatically when it becomes dark. CONSTITUTION:A light entering a photosensor 4 is turned into an electric signal, and whether or not it has lightness of a certain level or above is determined therefrom by a subsequent luminous intensity detector 5, whereby a relay 2 is connected. Therefore a power from a plug 1 passes through the relay 2 and is supplied from a receptacle 3 onto the appliance side. When it becomes dark, a power source is cut off contrariwise. In the case when a selector switch 6 is connected, a load detector 7 operates not to make the relay 2 operate when it gets light, although an operation made when it gest dark is the same as the above. It is necessary to break once a switch on the side of the appliance to be a load and to make it again in order to make the relay 2 operate, and consequently it is prevented that the power source is made arbitrarily. |
