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Old 1st Dec 2015, 11:04 pm   #86
bikerhifinut
Octode
 
Join Date: Nov 2013
Location: Penrith, Cumbria, UK
Posts: 1,993
Default Re: Test equipment for valve radio repair

Quote:
Originally Posted by Herald1360 View Post
Mmmmm.Typical DMM is 10M input resistance. AVO8 on 500Vdc range is also 10M input resistance. Tricky call.

A serious bench DMM like the HP 34401A does have a hi z input (Gohms) selectable on its lower voltage ranges. Useful for measuring voltages across hundreds of Kohm resistors.
I never really gave that any thought. So a reading taken across a 1M resistor will be 10% out?
I always took Moving coil measurements with the effect of the shunt resistance across the DUT but have to admit never thought that much about the DMM.
Guess that means the voltages on service sheets taken with AVO8's on the 500V range would tie in pretty well with those taken on a DMM there or thereabout?

Andy.
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