Author Topic: DVM High Megohm Range  (Read 176 times)

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Offline Ron Reeland

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DVM High Megohm Range
« on: January 08, 2020, 08:15:35 pm »

I have two digital meters from "Circuit Specialists' that have a 200 Meg-ohm range. Of course they are of Chinese origin but branded "Circuit Specialists".
They are very accurate on resistance ranges when tested with various values of precision resistors of 0.1 percent tolerance. Except the highest range of 200 Meg-ohms. Both meters will not "zero" on that range when probes are shorted. One displays 10.19 megs and the other 1.0 megs with shorted probes.

However if I test each meter with say a 150 Meg-ohm resistor, the result is very accurate as long as I subtract either the 1.0 meg or the rather unwieldly 10.19 meg figures.

Are there any internal adjustments to zero out the 200 Meg range? Or is non-zero oddity a quirk of very high meg-ohm ranges on all meters? Other meters I have seem to have a top range of 40 megs or so. They do zero properly at those lower ranges.

Ron Reeland

Offline retiredcaps

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Re: DVM High Megohm Range
« Reply #1 on: January 08, 2020, 08:41:06 pm »
What is the exact model?

Please post clear focused pictures of both pcbs.  We/you are looking for any debris, dust, oops moments, etc.

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