| 摘要 |
A method and an electrical measuring apparatus (10) for analyzing an actual alternating voltage present on an electrical wire (11) or electrical equipment whereby to determine if the voltage originates from a high or low impedance source for the safety of the operator. A bi-impedance (12) probe is connected to the alternating voltage to be analyzed and the voltage signals are processed. The actual probe consists of a first series of uni-directional (13) elements and a second parallel series of high value resistance elements (14). The output of the parallel connected series of elements is connected to a third series of low value resistance elements (15, 16, 18). A measuring circuit (17) is connected to the third series of low value resistance elements and is capable of discriminating between the voltage signals from both of the series of resistive elements and is provided with a calculating circuit (28) to determine if the voltage signals originate from a high or low impedance source. The output of the probe is connected to ground (19). An indicator (32) indicates the condition of the impedance source. An alarm indicator (32) may indicate if a predetermined threshold value, representative of a low impedance source, is exceeded.
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