Author Topic: Voltage Reference  (Read 746 times)

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Offline Rafael

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Voltage Reference
« on: March 10, 2018, 06:23:10 pm »
Hello Voltnuts...

Please, I got a 10V Voltage Reference Standard from eBay where the promise is+-2ppm.

The seller guarantees that he is calibrated and is only blaming the humidity of the environment.

Thanks a lot.
« Last Edit: March 12, 2018, 01:12:48 pm by Rafael »
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Online TiN

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #1 on: March 10, 2018, 06:53:58 pm »
Seller cannot guarantee you promised spec on that little box (have a read if you bored and have good sense of humor), but also you need keep both meters in high-impedance mode and 8846A might cause errors when connected together with other meter. You may want to have both meters connected one at a time. And anyway calibration performance even for freshly calibrated 34401 and 8846A is far worse than 2ppm.

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Offline glarsson

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #2 on: March 10, 2018, 06:57:44 pm »
Please, I got a 10V Voltage Reference Standard from eBay where the promise is+-2ppm.
Did the seller promise an absolute accuracy of 2ppm, a drift per day/month/year of 2ppm or a drift of 2ppm per kelvin temperature change?
« Last Edit: March 10, 2018, 06:59:17 pm by glarsson »
 

Offline IanB

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #3 on: March 10, 2018, 07:05:01 pm »
There's no way a little black plastic box from eBay is going to match the performance of those expensive multimeters. I'd say the reading you are getting is not bad, considering...
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Online TiN

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #4 on: March 10, 2018, 07:13:26 pm »
Sorry, read the user manuals. They have good Info's. Its 3am here now :(
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Online 2N3055

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #5 on: March 10, 2018, 11:29:02 pm »
There are few threads "dedicated" to this scam... for instance :https://www.eevblog.com/forum/metrology/calibratory-d-105-dc-precision-voltage-reference-standard/
I'm afraid you got "kaysered"... You should have bought on of "those small boxes of reference of china AD584H"... They would be comparable in specs and much much cheaper...
Also, http://www.voltagestandard.com/-.html] [url]http://www.voltagestandard.com/-.html [/url] actually works as specified.... For much less money...

 

Offline MasterT

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #6 on: March 11, 2018, 01:22:45 am »
I wander, if X-ray screening at the custom /inspection station could be blamed. My google search on topic brings this doc :
https://www.intersil.com/content/dam/Intersil/documents/an15/an1533.pdf

Does such issue exist with all highly priced metrology equipment, and how it could be avoided?
 

Offline Gyro

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Re: 10V DC Voltage Reference Standard - What's wrong...
« Reply #7 on: March 11, 2018, 10:24:21 am »
No, those Intersil references use charges stored on floating gate FETs as their reference. Very easy to produce custom voltages but very sensitive to Ionizing radiation, x-rays etc which drains the charge away - just like UV EPROMS.

It's a very different mechanism to other references, to change the voltage of a buried zener would require very large amounts of radiation to damage the atomic structure of their junctions.

EDIT: The problem with the OP's reference probably is humidity - if you check back through the referenced threads about it, it uses an Epoxy packaged REF02 rather than hermetic, making it very humidity sensitive (at the level of precision involved). The claims about its accuracy took no account of that (though a few weasel words have now been added to the listing).
« Last Edit: March 11, 2018, 10:37:45 am by Gyro »
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