Battery in VTVMs

[Andy E]

FWIW....

I'm not sure who to respond to, or who's still interested --
but here's my $0.02.


It may well be worth retaining the battery circuit for the OHMS
function.  The battery source is used because it is the least expensive,

pure DC source for resistance measurement.  Powering the OHMS
circuitry from AC would involve a fair amount of rectification and
filtering; yet in the end, you will still have a certain degree of
ripple.

Keep in mind that any ripple at all is AC with a DC bias, but AC
nonetheless to a circuit.  AC in any form (ripple, pulse, whatever)
will generate reactances (even in some seemingly simple circuits,
depending on operating frequency, physical design, et cetera).
So, on your sensitive OHMS ranges, your measurement will be
impedance (resistance+reactance) and not the pure resistance that
the OHMS function is designed to measure.

Perhaps converting the disposable battery circuit to a rechargeable
circuit would be a better way to go (I think someone else
suggested this too on LISTSERV), but this is a "quality of life"
decision.

Thx for reading.

Andy Eisenberg

Sponsored by the City of Tempe 

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