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Old 15th May 2018, 10:40 pm   #3
Phil G4SPZ
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Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,735
Default Re: Very high input resistance voltmeter

Good idea, that. Back in the day when DAF96s needed their voltages measured, most service departments would have still been using Avo Model 7s! Or a proper valve voltmeter with a cathode follower input stage. I have some Heathkit VTVMs, but even they have a resistive input attenuator which fixes the resistance to a disappointing 10 Megohms on all DC ranges.

The Avo EA113 electronic multimeter offers a genuine 1 Megohm-per-volt sensitivity as standard, or 100 Megohms on the 100V range and above. The much older Avo Electronic Testmeter also has a very high input resistance.
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