| 摘要 |
PURPOSE:To make the abnormal condition of a electric discharge lamp detectable in an accurate manner by comparing each of detected interelectrode voltage between both upper and lower limit values to be preset by a comparing device. CONSTITUTION:A voltage detecting device, detecting interelectrode voltage of an electric discharge lamp 1, comparing devices 6 and 7, comparing the interelectrode voltage each between both upper and lower limit values to be preset, and a delay device 11 where a malfunction detecting signal out of these comparing devices 6 and 7 is outputted as being delayed are included. That is to say, the interelectrode voltage is the discharge lamp 1 is detected by the voltage detecting device, and the detected interelectrode voltage is compared each between both upper and lower limit values to be preset by these comparing devices 6 and 7. The malfunction detecting signal out of suchlike comparing devices 6 and 7 is outputted after being delayed by the delay device 11. With this constitution, an abnormal condition of the discharge lamp is accurately detectable. |
