| 摘要 |
PCT No. PCT/GB89/00959 Sec. 371 Date Feb. 7, 1991 Sec. 102(e) Date Feb. 7, 1991 PCT Filed Aug. 17, 1989 PCT Pub. No. WO90/02340 PCT Pub. Date Mar. 8, 1990.For detecting whether a probe (P) is in contact with an electrical circuit under test (U), capacitance measurement means (M) measures the capacitance between the probe and a reference (G), without the probe contacting the circuit. The measured capacitance is stored in control circuitry (T) and then a capacitance value is measured between the probe and the reference with the probe in a position in which it is assumed to be in contact with the circuit, the control circuitry comparing the measured value with the stored capacitance.
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