Patent ID: 7554333

Claim:
A grounding detector to detect the grounding of a circuit that is connected to a power supply, the grounding detector comprising: a coupling capacitor that is connected at one end of the capacitor to an output terminal of the power supply and that is connected at another end to a measuring point; a voltage detector that detects a voltage amplitude generated at the measuring point; a pulse generator that generates a pulse signal with a prescribed frequency, applies the pulse signal to the measuring point, and generates a modified pulse signal having a modified frequency when the voltage amplitude detected by the voltage detector goes outside of a prescribed voltage range, the modified frequency being set below the prescribed frequency that existed when the voltage amplitude detected by the voltage detector is within the prescribed voltage range; and a grounding occurrence detection unit that detects the occurrence of grounding of the circuit based on the voltage amplitude detected by the voltage detector at the measuring point during the application of the pulse signal to the measuring point.