| 摘要 |
The apparatus for automatically coupling an internal ground of an electric appliance to an external ground, comprises first and second AC power lines for supplying an AC input to a load; a neutral ground generating circuit for combining the first and the second AC power lines to produce a neutral ground point; a first detection circuit for detecting a current flow from the first AC power line to the internal ground to generate a first current detection signal; a second detection circuit for detecting a current flow from the second AC power line to the internal ground to generate a second current detection signal; and a ground coupling circuit for connecting, in response to the second current detection signal, the first AC power line as the external ground to the internal ground; for connecting in response to the first current detection signal, the second AC power line as the external ground to the internal ground; and for connecting the neutral ground point as the external ground to the internal ground when the first and the second current detection signals are absent.
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