| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and method for detecting a direct current earth, which reduce fluctuation in earth detection sensitivity due to voltage fluctuation, with a sequentially movable earth terminal.SOLUTION: A device for detecting a direct current earth which includes: a series circuit composed of a resistor R1, a Zener diode ZD as a constant voltage element, and a resistor R2, connected between an anode side P and a cathode side N of a direct current circuit including a power source; and a switch SW which is arranged to switch a junction Tbetween the resistor R1 and the Zener diode ZD and a junction Tbetween the Zener diode ZD and the resistor R2. Midpoint potentials Eand E, which are potentials at the junctions Tand T, are periodically switched. An earth is detected from the potentials at the two points. |
