| 摘要 |
PURPOSE:To prolong the service lives of fluorescent lamps or incandescent lamps so that the lamps can be stably controlled by connecting loads to secondary windings of a plurality of current transformers and, at the same time, connecting in series the primary windings of all current transformers to a high- frequency constant-current power source. CONSTITUTION:Before fluorescent lamps 5a, 5b, and 5c start discharge, current transformers 4a, 4b, and 4c are saturated and no electric current hardly flows to the secondary windings of the transformers 4a, 4b, and 4c. After the lamps 5a, 5b, and 5c start discharge, discharge currents decided by the values of the currents flowing to the primary windings and turn ratios of the transformers 4a, 4b, and 4c respectively flow to the lamps 5a, 5b, and 5c through capacitors Ca, Cb, and Cc and the terminal voltages of the secondary windings are stabilized under a condition where the terminal voltages drop to discharge voltages corresponding to the discharge currents of the lamps 5a, 5b, and 5c. While the current flowing to the secondary winding of a current transformer 4d flows to the filament of a incandescent lamp 5d from the beginning, the lamp becomes brighter as the filament is heated and its resistance increases and reaches a steady state. |
