| 摘要 |
PROBLEM TO BE SOLVED: To detect automatically whether an equipped lamp of an lighting system is a fitted lamp or not without driving a lighting circuit or an ignitor circuit, and to enable a lamp to light automatically only in case of a fitted lamp. SOLUTION: Current is carried to an equipped lamp from a direct-current power source 2, bypassing a switching element 13 of a lighting circuit 3. As an element for detection 42 (resistance or the like), connected with an arc tube 41 in parallel, is installed in a high-voltage discharge lamp 6 which is a fitted lamp, the equipped lamp can be judged by a magnitude of its divided voltage whether it is a fitted lamp or not. The result is detected by a lamp-equipment detecting circuit 5, and in the case of a fitted lamp, the operation of a driving circuit 11 is started by a control circuit 12. |
