[time-nuts] any way to bootstrap a frequency standard into a voltage or resistance standard?
bruce.griffiths at xtra.co.nz
Fri Nov 28 05:44:12 UTC 2008
Scott Burris wrote:
> Now that many of us have a nice 10Mhz reference courtesy of TAPR,
> I was wondering if there was any way to use that to build a precise
> voltage or resistance standard?
> I've got once of those high precision standard resistors with a sticker
> on it noting the actual measured resistance. Is it still accurate? Who
> As well, I have a +5v reference that uses an Analog Devices precision
> reference chip as its source. I have more faith that this reference is
> correct within the tolerances specified in the datasheet.
> Now if I could somehow take that frequency reference and derive a
> voltage standard or the like, I'd be in business. But I can't think
> of a way that wouldn't require calibration of some sort, and if I had
> the means to calibrate, I wouldn't need the standard in the first place.
> Any voltage-nuts or resistance-nuts out there?
1) Frequency to voltage via the Josephson effect.
2) Resistance standard via the quantised Hall effect
3) Resistance caibration via a calculable capacitor (Thompson Lampard
theorem) and an AC bridge (excitation frequency has to be accurately known).
The Josephson voltage standard requires an array of Josephson junctions
immersed in Liquid helium and excitation by a stable microwave source.
The quantised hall effect also requires a cryostat.
The calculable capacitor requires accurate length measurements
(frequency stabilised laser or equivalent).
More information about the time-nuts