| 摘要 |
PURPOSE:To make the construction of an emergency lamp lighting system and at the same time to improve reliability of it operation, by connecting a semiconductor switching element in the emergency lamp lighting circuit and controlling its operation by means of light emitting and receiving element. CONSTITUTION:In normal condition, light is emitted from light emitting element 27 with connection of Ac power source 21, and light receiving element 28 having received the light from the light emitting element 27 de-energizes semiconductor switching element 29, so that lamp 30 is kept in its OFF-condition and battery 26 is charged by DC current. On the other hand, when power source 21 is disconnected at the time of emergency, semicondutor switching element 29 is energized by the light receiving element 28 so that lamp 30 is turned ON by the current supplied from battery 26. Further, a screen plate 31 is disposed between the above two elements 27 and 28, in the manner that it is moved by pull string 32 to a position capable of screening the light from element 27 temporarily, whereby it is enabled to detect with ease and correctness whether some trouble is caused with the system or not. |
