| 摘要 |
PURPOSE: To extend the operating life of a gas discharge tube by providing a power supply operating the gas discharge tube with an adjusting current and a limiting voltage maintaining the input/out power of the gas discharge tube at the prescribed value on a ballast containing a filter circuit and an induction circuit. CONSTITUTION: A ballast 10 is provided with a power supply 12 for a gas discharge tube 66. The ballast 10 contains a filter circuit 11 connected to the power supply 12, stabilizing DC current and voltage signals, and suppressing the harmonic waves generated by the ballast 10. The ballast 10 also contains an induction circuit 15, and the induction circuit 15 is electrically connected to the filter circuit 11 and establishes the size of the pulse drive current with a switching network 13. The induction circuit 15 contains a no-load protection circuit 99, generates a voltage in the gas discharge tube 66 in response to the pulse drive current, and maintains the output voltage at the prescribed value even when the gas discharge tube 66 is not electrically connected to the ballast 10. The operating life of the gas discharge tube can be extended. |
