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Re: High voltage probe, odd NST measurements



Original poster: Ed Phillips <evp@xxxxxxxxxxx>

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

Hi Ed,

Yes, over compensation will cause high readings.  One might calculate
how much capacitance it takes across each resister to properly
compensate.  I'm guessing this is an order of magnitude larger than
the strays and may be hard to accidently do.

Gerry R."

If I remember the original design correctly it uses a 10G ohm (10^10 ohm) series multiplier. At 60 Hz an 0.265 pF capacitor would have that reactance and cause ~ 41% high error. That's not much capacitance at all!

Ed