| 摘要 |
<p>PURPOSE:To immediately light a filament of waiting system at the filament disconnection of a bulb, and prevent the interruption of lighting. CONSTITUTION:A filament 8a is heated by the opening of a switch 13. A filament current 1A is detected by a current transformer 10, and a DC power source is supplied to a control part 11 from a switching regulator 12 to operate the control part 11. When the output of the current transformer 10 is suddenly changed by the disconnection of the filament 7a, the control part 11 detects this and outputs a DC Voltage to terminals D1, D2. Thus, a filament 8b is lighted. When the filament 8a is disconnected, a LED 14 is lighted. An operator knows that the filament is changed to waiting system by this.</p> |
