| 摘要 |
PURPOSE:To monitor the disconnection of LEDs used for the light emitting source of a signal lamp. CONSTITUTION:A plurality of LEDs 9, 9,... packaged on a substrate are divided into two or more sets and series circuits C1-C40 of each set of LEDs are connected in parallel to a power supply circuit. A detection element 12 is provided at the series circuits C1-C40 of each set of LEDs. The result of AND operation of each sets of detection elements 12 is output and a relay 15 is operated under the conditions where the AND conditions are false, thus outputting failure occurrence information. |
