| 摘要 |
A testing device for single-pole voltage testing comprises, between a test electrode (1) and a ground electrode (2), a high impedance dropping resistor (R1) and a measurement resistor (R2) connected in series. The ground electrode (2) is capacitively coupled to earth through the body of the user. The value of the dropping resistor (R1) is at least 10 times greater than the maximum variation which occurs in the capacitively coupled reactance (C1, C2) of the user relative to the ground, so that the total impedance is almost constant. The voltage drop across the measurement resistor (R2) is amplified, rectified and compared in a comparison circuit with predetermined reference voltages in order to control a light emitting diode indicator (D2, D3, D4, D5) corresponding to the measured voltage. The test device can also be constructed for contactless voltage testing or can also be used as a continuity tester.
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