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Re: High voltage probe, odd NST measurements



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Michael,

Correction:  BW = 1/(2*pi*RC) or about 1600Hz

Gerry R.


Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
Hi Michael,
Replace your 1M ohm resister with a 1.1M resister and you will be close to a 10000:1 probe.
For the RC time constant, you would use 1 Mohm for R (thevenin resistance of the divider - 10Gohm || 1.1Mohm || 10Mohm). Dont know what the input capacitance of the meter is but if you assume 100 pf, the RC time constant would be 100us. The BW would be 1/(2.2*RC) or about 4500 Hz.
Gerry R.


Original poster: Michael S <mike5904@xxxxxxxxx>

Well looking at the meter specifications I see a 10M impedance, which
would lead to a ratio of 11000:1.  I wouldn't know how to go about
measuring the effect of meter capacitance on frequency response but at
least the measure for the NST was "close enough" for my purposes.