[time-nuts] App Notes Voltage References

Steve Rooke sar10538 at gmail.com
Sun Nov 30 01:51:16 UTC 2008


2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:

> Since these devices actually store the reference voltage on an internal
> capacitor, it would be interesting/informative to plot the output as a
> function of time over several years/decades.
> They haven't yet been available for long enough to establish their long
> term stability in actual use.
> I wonder if one can recharge the internal capacitor should this prove
> necessary or if one wanted to adjust the output?
> This probably requires access to an internal node.
> During manufacture, a servo loop adjusts the output by changing the
> voltage on the internal capacitor until the output reaches the voltage
> of the external precision reference.
> The servo loop is then opened trapping the required charge on the capacitor.

I guess that would require having a suitably accurate measuring
instrument with an accurate reference voltage in the first place.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet




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