You will find that most old "stuff" does not drift as much as the new "stuff". Most resistors seem to drift in a damped sine wave rate with a period of about 4 years.
On Thu, Aug 8, 2013 at 10:10 AM, Didier Juges <[email protected]> wrote: > I had my eBay special $90 HP3478A calibrated by our internal cal lab > (traceable to NIST). Based on the sticker, the last cal was 5 years old. > The instrument was well within all specs by a wide margin (most readings > were within 20% of the stated tolerance, which after 5 years is pretty good. > > Didier KO4BB > > Roy Phillips <[email protected]> wrote: > > > > > >-----Original Message----- > >From: Electronics and Books > >Sent: Thursday, August 08, 2013 12:54 PM > >To: Discussion of precise voltage measurement > >Subject: Re: [volt-nuts] DMM calibration > > > >Specs for a 3478A > > > > > >Brand HP Model 3478A Counts 303.099 TrueRMS X Display LCD Year 1983 > >Range > >Stability [ppm] Low High Resolution 1y > >DC Volt 30m 300 100n 60 AC Volt 300m 300 1u 2000 Max Frequency 300k > > > >Resistance 30 30M 100u 160 DC Current 300m 3 1u 1500 AC Current > >300m 3 > >1u 7200 Interface GPIB Battery backup X > >If you do the adjustments with some hobby equipment wich an accuracy of > >say > >20 to 30 ppm. Thats all within limits of this multimeter. You never see > >the > >difference. > >In my opion, expensive adjustments and calibration for not so accurate > >equipment is a waste of money. Especialy when the calibration price > >exceeds > >the equipment price. > > > > > > > > > > > >Regards > > > > > >[email protected] > >http://ElectronicsAndBooks.com > > > >I would like to say - "you are absolutely correct" - I have recently > >been > >quoted for a 3458A which requires a new set of ROM's and re-cal. - the > >cost > >was greater than I paid for the S/H instrument just 4 years ago. These > >prices are OK for large Companies who can recover the VAT for a start ! > > > >......... but cannot be justified for hobbyists. Most of us have items > >of > >equipment that have been calibrated in recent times, and other > >precision > >items like resistors and higher spec. zeners that when you make > >comparisons > >can verify your DVM's . I recently purchased a Keithley 2015 for less > >than > >some cal. charges, this was calibrated in 2008 and I would say that it > >is > >still in very good calibration now. > >Roy P > > > > > >________________________________ > >From: "Marv @ Home" <[email protected]> > >To: Discussion of precise voltage measurement <[email protected]>; > >Discussion of precise voltage measurement <[email protected]> > >Sent: Wednesday, August 7, 2013 6:53 PM > >Subject: Re: [volt-nuts] DMM calibration > > > > > >I don't know what logo cal is, but between Z540 and 17025 is a > >question of procedures and how they are done. > >In metrology the procedures, and how strict they are, reduce the risk > >of uncertainty in the final measurement. For example, some > >procedures in Z540 can be 'interpreted' where in 17025 is explicit, > >thus there is more room in Z540 for one lab to be worse than another, > >or vice versa, which defeats the purpose of standardization. This > >'intepretation' is fairly reduced when the device is cal'd by an > >autocalibrator such for close case calibration DMMs, but becomes a > >big issue with any manual cal. > > > >If these do not mean anything to you and you do not need the data for > >long term drift calculations, ISO 9001 is good to go. > > > >IMHO the difference between all 3 is insignificant for 5.5 digit > >DMMs, except for one's need for data. > > > > > > > http://us.flukecal.com/literature/articles-and-education/temperature-calibration/papers-articles/comparison-ansincsl-z540-1?geoip=1 > > > >At 12:30 PM 8/7/2013, Joseph Gray wrote: > >>I just got the following quote for getting my HP 3478A calibrated. > >> > >>35.00 for ISO 9001 no data > >>87.50 for Z540 with data and uncertainties > >>275.00 for 17025 with data, uncertainties and logo calibration. > >> > >>I still didn't get any explaination as to exactly what the lab does > >for > >>each of these price points. When I asked about the "Level 4" listed > >next to > >>the meter, I was told that it is the difficulty level. Still not > >telling me > >>much. I have read the procedure in the HP service manual and it is > >very > >>easy. You set some volt, amp, ohm values on the standard, then push > >some > >>buttons on the meter. > >> > >>I understand about getting data or not, it is the other aspects that I > >>don't understand. What is Z540, 17025 and "logo calibration"? > >> > >> > >>Joe Gray > >>W5JG > > > > > > > >Sincerely, > > > > > > > >Marv > >Philadelphia, PA > > > >_______________________________________________ > >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. > > -- > Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other > things. > _______________________________________________ > 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. > -- John Phillips _______________________________________________ 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.
