| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To realize an LED signal lamp and a railway signal that can be used under the same voltage without performing resistor switching even under a series connection of two lamps and a single lamp. <P>SOLUTION: This LED signal lamp 50 comprises a fitting or disengaging unit having a fitting 21 replaced in a railway signal lamp and a connecting contact portion 22; an LED unit having a plurality of LEDs 52a and 52b connected in such a way that they can be driven concurrently; a rectifier circuit 31 inserted at an electrical power path extending from the connecting contact portion 22 to the LED; and current control circuits 51a and 51b for restricting the current in the electrical power path to an allowable range of the LEDs. In addition to LEDs, the current control circuit is also divided into two groups, and a series connection/parallel connection changing-over circuit 56 capable of changing-over whether or not the two groups are set in a series-connected state or a parallel-connected state is installed. When this is installed at a railway signal unit, the two groups are switched into a parallel-connected state in the series connected two lamps and the two groups of one lamp are switched to a series connection. With such an arrangement as above, all the light emitting signal lamps are lit and driven at a rated voltage. <P>COPYRIGHT: (C)2004,JPO</p> |
