[volt-nuts] AC Voltage Measurement Standards
tmicallef at gmail.com
Wed Jul 9 12:35:39 EDT 2014
I would like to know more about your setup. Which source(s) are you using
for the input and which nanovoltmeter(s) are you using to transfer the 10V
TVC to your other converters? I remember you asking on PMEL forum about the
accuracy of using a 34420A nanovoltmeter. I did not see a response as to
whether you opted for an alternative like Keithley 2182(A) or a low noise
preamplifier connected to a 3458A.
I have done some reading about how NIST transfers their calibrations using
two TVC's in parallel and I am guessing that is what you are doing.
To transfer the accuracy up/down to other TVC's at different rated voltages
appears to be a difficult task since they typically need at least half the
rated max voltage to be within spec. It would be similar to starting with a
SR104 standard and transferring its value through a set of SR1010 and
SR1050 resistors using an ESI 242.
I have a few AC sources, and I would like to be able to verify my TVC's
without sending all of them out for cal. Ballantine quoted $600+ per TVC
and I haven't checked what Fluke would charge for each A55.
I personally did the following: I got a Ballantine 1605A transfer
> voltmeter. This is comparable to the 792A in a way, except it was much
> cheaper. It is automatic, much easier to use than the Fluke 540 and goes up
> to I think 100MHz. This can be used for percision calibrations as a working
> standard. The calibration of this meter as well as others (e.g. the 3458A
> in its AC mode) I am doing with a set of thermal converters (0.5V to 100V).
> One of which (10V) has been externally calibrated up to 30MHz, cal of the
> others are derived from it. That way I am deriving everything from a very
> precisely (few ppm) calibrated 10V TVC. Overall, this saves cost on the
> calibration side, allows for high accuracy and measurement speed is good.
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