| 摘要 |
PURPOSE:To grasp the discharge state of a discharge lamp without electrodes accurately, by providing an electric characteristic detecting means, which is constituted by winding a detecting winding around a ring-shaped core that is interlinked with the discharge lamp without electrodes. CONSTITUTION:The title apparatus is composed of a discharge lamp 1 without electrodes, a coil 2 which is arranged around the outer surface of the discharge lamp 1, and an electric characteristic detecting means 6, which is constituted by winding a detecting winding 5 around a ring shaped core 4 that is interlinked with the discharge lamp 1. When a high frequency current is made to flow through the coil 2 from a power source 3 and the discharge lamp 1 emits light, high frequency magnetic flux, which is proportional to the current of the lamp, flows through the winding 5. Therefore, the waveform of the lamp current and the value of the lamp current can be measured from a voltage across a load resistor 7, which is connected to the winding 5. The discharge state when the discharge lamp 1 is started or turned ON can be accurately grasped. |
