'Cancelling' part of a meter's impedance?
This is a follow on from my post previously checking on my maths regarding measuring high voltages,
My an unlucky coincidence, my DMM has an impedance of 11Mohm, rather than the expected 10Mohm. With my first built 10:1 resistor chain, I could select resistors to allow me to include a series preset to adjust for exactly 10:1 readings,
Ive now obtained a 1Gohm resistor for 100:1, but of course the numbers are not coming out exactly 100:1 due to the meters rather odd extra Mohm!
Im wondering if I can 'cancel' this extra M of the meters impedance using a parallel resistor? This would need around an extra 100M which I could make up using low voltage resistors from stock, including a preset to trim the readings to an exact 100:1.
Ive never tried this method with a meter, and dont seem to be able to find any info on whether it works. I'd make up a parallel resistance and try it, but im out of 10M units at the moment (on order) and its a bit much to mock up 110M from smaller values!
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