Device for detecting broken filaments in lamps

摘要

In a device for detecting broken filaments of lamps which are connected with secondary windings of transformers respectively provided for the lamps, primary windings of the transformers being connected in series across an AC power source through a power control device, there are provided a detector for detecting voltage and current delivered from the power control device, and another detector for detecting a phase difference between the voltage and the current thus detected by the voltage and current detector.