| Electronics > Metrology |
| Known voltage source for checking calibrations... |
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| george graves:
I think I'm really unlucky with buying test equipement. Either my year old Rigol 1052E isn't measuring voltage correctly, or my 6 month old Fluke 87-5 is messed up. I say that because when I hook them up to to the same source, the Rigol will read about 10% different. Anyways, I'd love to figure out what one is incorrect, so that I don't have to send BOTH in - and not only that but I'd love to check them against a known standard occasionally so that I don't feel like I feel right now (slowly loosing my damn mind over it!) I found this: http://lategahn.2log.de/index.php?calibration-standards-introduction --- Quote ---Linear Technologies offer the lovely LT1021CCN8-10, basically a voltage stabilizer which can generate a very low drift 10V voltage with up to 10mA of current and an initial tolerance of 0.05% without the need for external adjustment. --- End quote --- The voltage "standard" looks very promising. Any thoughts on such a set up? Thanks! |
| saturation:
Its OK but you'll still need to calibrate the output of your design to determine what exactly the voltage is. Over time it will drift and it needs to be characterized and stabilized. We have a very detailed discussion on voltage standards here. https://www.eevblog.com/forum/index.php?topic=1652.0 https://www.eevblog.com/forum/index.php?topic=650.0 https://www.eevblog.com/forum/index.php?topic=601.0 I'm maintaining one to 10uV accuracy but it takes a lot of work, even if you just buy a premade reference as per the links. However, if you buy a precision hobbyist reference good to the uV, but only require it for testing to mV, it should be good for years after you purchase it from Geller or voltagestandard.com and the unit is properly made. The reason is after calibration, and excluding periodic variation with weather and climate through the year, it could drift at worst + 100uV/year [see the spec sheet of the chip you choose, 100uV is a really worse case 'cheapo' reference]. At that rate, it will need 10 years before it registers 1mV out of calibration on the mV scale. |
| Kiriakos-GR:
--- Quote from: george graves on January 05, 2011, 12:27:30 pm --- I found this: http://lategahn.2log.de/index.php?calibration-standards-introduction --- Quote ---Linear Technologies offer the lovely LT1021CCN8-10, basically a voltage stabilizer which can generate a very low drift 10V voltage with up to 10mA of current and an initial tolerance of 0.05% without the need for external adjustment. --- End quote --- The voltage "standard" looks very promising. Any thoughts on such a set up? Thanks! --- End quote --- I have build it , works great !! ;) Check pictures and details here.. https://www.eevblog.com/forum/index.php?topic=1148.0 |
| FreeThinker:
--- Quote from: george graves on January 05, 2011, 12:27:30 pm ---I think I'm really unlucky with buying test equipement. Either my year old Rigol 1052E isn't measuring voltage correctly, or my 6 month old Fluke 87-5 is messed up. I say that because when I hook them up to to the same source, the Rigol will read about 10% different. Anyways, I'd love to figure out what one is incorrect, so that I don't have to send BOTH in - and not only that but I'd love to check them against a known standard occasionally so that I don't feel like I feel right now (slowly looking my damn mind over it!) I found this: http://lategahn.2log.de/index.php?calibration-standards-introduction --- Quote ---Linear Technologies offer the lovely LT1021CCN8-10, basically a voltage stabilizer which can generate a very low drift 10V voltage with up to 10mA of current and an initial tolerance of 0.05% without the need for external adjustment. --- End quote --- The voltage "standard" looks very promising. Any thoughts on such a set up? Thanks! --- End quote --- Sods Law predicts that it will be the (Just out of warranty ) Rigol thats at fault :D PS Have you tried to recalibrate your Rigol, may be a quick fix |
| Time:
I'd put my money on the Rigol being wrong. An oscilliscope is not supposed to be terribly accurate with voltage measurements in the first place. It would make a poor DC voltmeter if thats how you are testing it. |
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