| 摘要 |
PURPOSE:To enable the rapid and reliable checking of disconnection of an alarm lamp, by providing a pair of alarm lamps operating in response to the same abnormality signal and by making one alarm lamp lighted when the other alarm lamp is disconnected. CONSTITUTION:Alarm lamps 1A and 1B provided on a meter panel or the like are connected to a vehicle-borne battery 64 through a fuse 61 and a key switch 63. NPN transistors (Tr) 2A and 2B constitute first and second drive circuits respectively. PNP transistors (Tr) 3A and 3B constitute first and second disconnection detecting circuits respectively. In response to the same abnormality signal 4a of a vehicle-borne apparatus, the Tr 2A and 2B operate simultaneously to make the alarm lamps 1A and 1B lighted. When the lamp 1A is disconnected on the occasion, this is detected by the Tr 3A, and thereby the Tr 2B is operated to make the lamp 1B lighted, so as to inform the disconnection of the lamp 1A. When the lamp 1B is disconnected, the lamp 1A is lighted in the same way. A driver of a vehicle can check reliably the abnormality in the vehicle- borne apparatus from the information issued by the lamp 1A or 1B. |
