| 摘要 |
PURPOSE:To maintain a normal lighting condition by the current from a main power source and a ballast resistance when the voltage of the electrode tube of an electric discharge tube in glow discharging drops and whereby moving to an arc discharge region. CONSTITUTION:A drive main power source 7 required for starting the electric discharge of an electric discharge tube 1 and a high voltage power source 4 are connected together in series, and a reverse current preventing element 5 in the side of the power source and a side path element in the side of the main power source 7 are connected together in parallel to one another. The function of each power source is activated according to the condition of voltage between both electrodes at the time of discharge starting or lighting condition of the electric discharge tube 1. When the voltage between the both electrodes of the electric discharge tube 1 at the time of flow discharging is lowered, the current from the main power source 7 and a ballast resistance 6 starts to flow. Discharging is moved to an arc discharging region as the amount of currents is increased, and normal lighting condition is maintained by the electric discharge tube 1 responding to the negative characteristic of the electric discharge tube 1. |
