| 摘要 |
PURPOSE:To determine a level for detecting whether under charging or not at a suitable value and to improve the accuracy of the phase to be detected, by disposing a detection part having the 1st level detection circuit and the 2nd level detection circuit between an AC transmission and distribution wire and the ground. CONSTITUTION:The 1st level detection circuit 25 outputs the detection of a charging state when the voltage at both terminals of a capacitor 23 for detection is larger than a detection level V1. A switching circuit 27 generates an ON output upon receiving said output. A flicker circuit 32 and a driver circuit 33 are actuated by the ON output and a pilot lamp 19 starts flickering. At the same instant, the 2nd level detection circuit 26 outputs the low frequency signal to a mixing circuit 30 only when a low frequency oscillator 28 is in the high level period when the voltage at both terminals of capacitors 22, 23 for detection exceeds the detection level V2. When the circuit 27 produces the on output, the mixing circuit 30 outputs the high frequency signal modulated with the low frequency signal to a high frequency amplifier 31 only in the high level period of the square wave and said signal is emitted from a transmission antenna 11. |
