Hi Joe, To check the differences between the two references, connect the commons and put your 3478A meter beween the positive outputs. The meter will read the difference. As it should be less than 3V the 3478A will be in high impedance mode so loading will be minimised. Reverse the connectons and average the two readings to eliminate thermal EMFs. If the VS330 has fine enough adjustment you can zero the indicated difference. If the average meter reading and the adjustment of the reference for zero match, you have a good confidence for the difference between the two standards. Now you just need a third standard, maybe a Kelvin Varley divider, another meter.............
Robert G8RPI, ________________________________ From: J. L. Trantham <[email protected]> To: 'Discussion of precise voltage measurement' <[email protected]> Sent: Saturday, 3 August 2013, 4:24 Subject: Re: [volt-nuts] VS 330 arrived Accidents do happen. No, just kidding. Probably means all three are very close. Joe -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Joseph Gray Sent: Friday, August 02, 2013 8:41 PM To: Discussion of precise voltage measurement Subject: [volt-nuts] VS 330 arrived The new toy that I don't really need arrived :-) According to my uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages are very close to expected values and the increments via the switches are consistent. Not knowing the accuracy of either the DMM or the VS 330, I still thought it would be interesting to see what reading I got on the DMM with the VS 330 set to 5.00000 VDC. If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. I still need to get both the DMM and the VS 330 calibrated, but it is interesting that the only two voltage standards that I have seem to be in close agreement. Joe Gray W5JG _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
