[Test-Equipment] rms voltmeter?

[k0ewu9 at juno.com]

HI ALL, i found an old westinghouse lab type ac voltmeter, actually a
dynamometer type movement

which is dc as well as ac...The original factory cal chart was still in
the lid, the unit was sold as a lab type with an accuracy of 0.25%

or better.  I took it down to our local ISO cal lab and checked it againt
the new fluke  cal standard,

it is still within the accuracy stated in the chart, it is running about
0.15 to 0.18% at half or full scale, pretty good for 

a 65 year old thing?

jack      K0EWU9 at juno.com


On Sat, 19 Jan 2008 16:07:11 -0800 (PST) david at slack.com (David
DiGiacomo) writes:
> >Anyone know what sort of "standard" one usually uses to calibrate an 
> "AC" 
> >indicating instrument?
> 
> An AC voltage calibrator such as an HP 6920, Fluke 515A, Fluke 
> 760A,
> Fluke 5100, or many others.
> 
> At higher frequencies, an oscilloscope calibrator/constant 
> amplitude
> signal generator such as the Tek 191 or SG503.
> 
> >It's much easier to find a DC voltage source that's accurate.  
> Where does 
> >one find an "accurate" (1% MAX or tighter)?
> 
> Again, there are many calibrators available, such as the units 
> above, and
> also DC only units such as the Fluke 332.
> 
> Or, you can find an old fashioned standard cell, often available 
> very
> cheaply, but a bit hard to use.
> 
> Or, you can build a standard out of one of many precalibrated IC 
> voltage
> reference ICs that are now available.  This has been discussed to 
> death,
> so I suggest you try a web search.
> 
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