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The relevant time constant is the product of the effective capacitance in microfarads and the6 l0 b0 `+ d( F4 W& G7 D, j
effective discharge resistance in megohms. If it is difficult to determine the effective5 w$ N/ i+ t* M6 n, g9 |
capacitance and resistance values, a measurement of voltage decay at the point of external5 e1 O3 H9 U. t2 P+ K
disconnection can be used. When conducting the voltage decay measurement, the result is
# [- f2 r6 [2 y* y' `* Ireferred to an instrument having an input impedance consisting of a resistance of
c9 R' G. W( ~& \# {& Z100 MΩ ± 5 MΩ in parallel with an input capacitance of 20 pF ± 5 pF.8 s9 t! v) t3 V$ R
从标准的内容来说,确实是要求100 MΩ ± 5 MΩ 阻抗,但是我个人觉得阻抗越大,分流就越小,测到的数据就越接近真实情况。但标准不知道是怎么考虑的,为什么不在100M前面加上at least 之类的字眼。 |
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