| 摘要 |
PURPOSE:To detect and display the lighting failure of a floodlight BX. CONSTITUTION:A lighting judging device for floodlight has a phase difference detecting circuit 11 for inputting the voltage V and current I supplied to a floodlight BX; a timer 12; and an indicator 13. Since the current I has a delay power factor of about 80-95% to the voltage V when the floodlight BX is lighted, and has a leading power factor of 0% because of a power factor improving capacitor built in the floodlight BX when the floodlight BX is extinguished, the phase difference detecting circuit 11 can judge the lighting state and extinguishing state of the floodlight BX. The timer 12 measures the unlighting time of the floodlight BX and operates the indicator 13 by a time-up signal S2. |
