So I have nothing to complain, after the first week changing " much" it now goes up/ down a bit with temp and probably humidity. At 10V, 1ppm is 10 uV so it is changes 5 to 6 ppm over 5 degrees. Today it changed less then 1 ppm over 3 degrees so I that leaves humidity. I do not have a hygrometer so it becomes time I get one.
Thanks for the tips for the common mode, i will try it soon, http://www.pa4tim.nl/wp-content/uploads/2011/06/lm399schema_1.jpg This is the schematic ( completely my own design but I'm no EE so it probably will not be to great) but I appriciate comments for improvement. http://www.pa4tim.nl/?p=2531 pictures are at the bottom of the page, all my reference experiments are here together. Fred PA4TIM Op 20 okt. 2012 om 17:41 heeft "Andreas Jahn" <[email protected]> het volgende geschreven: > Hello Fred, > >> It is now 24/7 on for about 5 weeks. > > 5 weeks is nothing in the life of a reference. > During the first year my 2 LM399 references drifted 500uV against each other > > The 2nd year it was only 220uV > now I know that LM399 #1 is drifting much more (200uV) than LM399 #2 (20uV) > in the 2nd year. > > In the 3rd year LM399#1 drifted around 140uV and LM399#3 less than 10uV. > > So not all references seem to be usable for precision measurement. > Its shurely no fault to start with a set of several references and select out > the bad ones. > > With best regards > > Andreas > > > _______________________________________________ > 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.
