Steve Rooke wrote: > 2008/11/30 Bruce Griffiths <[EMAIL PROTECTED]>: > >> Mark Sims wrote: >> >>> If you want to play with the Xicor references, I can recommend the device >>> sold by Ebay zildjianboy7 (Doug Malone) See current auction item >>> 280289828315. For $30 shipped, it makes for a very handy meter checker / >>> portable voltage reference. Not as stable as the Geller Labs board, but >>> it runs on a 9V battery. >>> >>> >> Beware of their large flicker and wideband noise. >> Because of the relatively high flicker noise, they wont, in practice be >> anywhere near as stable as a good zener based reference >> However they may be useful for checking lower resolution devices such as >> a handheld DMM. >> > > Thanks, that's exactly the use I had intended one for. > > 73, Steve > Steve
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. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
