On Sun, Aug 11, 2013 at 2:55 PM, Dr. David Kirkby <drkir...@gmail.com>wrote:
> > > How useful is this > > http://www.ebay.com/itm/281149723636 ? > > On the fact of it, the device would give one a reasonly high > confidence something is working readlably well. I wonder if that is > good enough for a 3457A. > It would give a reasonable check for gross errors. They do claim to be using a 3458A to cal them and give the 3458A cal certificate number. Personally, I use a Geller Labs SVR-T for voltage checks at 10V http://www.gellerlabs.com/Voltage%20References.htm Joe Geller's calibrations are NIST traceable through his Fluke 732B. A new Agilent 34461A reads the SVR-T at about -3ppm, though it's a moving target due to the temp-co of the '61A. The goldenrubi supplied 3456A reads the SVR-T at 8ppm high - inside 24 hour specs, but uncertain given the SVR-T's claimed transfer accuracy of 5ppm. I also have a Geller SVR that has been back twice for calibration. The first time back it was found to have changed by 1ppm. The second time back, I specified a different temperature so there was no as received data. The SVR is a reasonable choice if your lab stays at a constant temperature. I should go get the kelvin clips out and compare the 3456A against the '61A on some 10k precision wirewound resistors I have. Orin. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.