Re: [volt-nuts] The "averaging reference"

2014-12-22 Thread Attila Kinali
On Sat, 20 Dec 2014 22:17:57 +0100 Joel Setton wrote: > I wasn't aware of the degraded long-term drift performance in the > plastic packages, as compared to the metal can. I'm surprised they can't > protect the chip from package-induced effects! Well, that's where physics strikes back... and e

Re: [volt-nuts] The "averaging reference"

2014-12-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 Dec 2014 21:18, "Joel Setton" wrote: > > Jan, > > Thanks for a good summary f the pros/cons. Of course the LTZ1000 is much closer to the current state of the art, but the REF102 is far easier to use and to calibrate. I'm definitely not shooting for sub-ppm performance, if I can build anythin

Re: [volt-nuts] The averaging reference

2014-12-20 Thread Todd Micallef
I believe the 1281 uses the LTZ1000. The datasheet mentions dual references. My 4920 has both a ltz1000 and a lm399. I think you can find pics of the 1281 dual ref setup on eevblog. I would not be surprised if the 8508a has a similar configuration. Todd On Saturday, December 20, 2014, Richard M

Re: [volt-nuts] The "averaging reference"

2014-12-20 Thread Joel Setton
Jan, Thanks for a good summary f the pros/cons. Of course the LTZ1000 is much closer to the current state of the art, but the REF102 is far easier to use and to calibrate. I'm definitely not shooting for sub-ppm performance, if I can build anything that stays within (say) 20 ppm long-term, th

Re: [volt-nuts] The averaging reference

2014-12-20 Thread Richard Moore
The Datron 1081/1082 are 7-1/2 digit meters. The zeners are two pair of two zeners in series to get the ref voltage up high enough. In the two 1081s I had, they worked quite well, ref’d to the two Fluke 732As I had at the time. But not 8-1/2 digit grade, I don’t think. I have no idea what the 1

Re: [volt-nuts] The "averaging reference"

2014-12-20 Thread Electronics and Books via volt-nuts
The Datron 1081 used 4 zener diodes Regards Frans ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.

Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread M K
On 19/12/2014 22:13, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 19 Dec 2014 19:30, "Jan Fredriksson" wrote: It's no coincidence that virtually all 8.5 digit DMMs use the LTZ1000. It's in a class of it's own. What do the 8.5 digit meters use if they don't use the LTZ1000? Dave. Well th

Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 19 Dec 2014 19:30, "Jan Fredriksson" wrote: > > It's no coincidence that virtually all 8.5 digit DMMs use the LTZ1000. > It's in a class of it's own. What do the 8.5 digit meters use if they don't use the LTZ1000? Dave. ___ volt-nuts mailing list --

Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread Jan Fredriksson
It's no coincidence that virtually all 8.5 digit DMMs use the LTZ1000. It's in a class of it's own. REF102 is not in the same class, even if you average a handful. But there are a couple of nice things about the REF102, though for more moderate requirements - You get a reference at 10V, +/-0.0025V

Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread Joel Setton
Guys, Thanks for your comments! The idea is to use a simple resistor averaging network, as shown in Fig. 14 of the REF102 datasheet. I hadn't thought of the effect of relative humidity, would the temperature-controlled enclosure at (say) 50C/122F change things in this respect? One nice thing a

Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread Joel Setton
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Re: [volt-nuts] The "averaging reference"

2014-12-19 Thread Joel Setton
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Re: [volt-nuts] The "averaging reference"

2014-12-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 18 Dec 2014 19:06, "Poul-Henning Kamp" wrote: > > > In message <5492f59e.8060...@free.fr>, Joel Setton writes: > > >In my search for the Perfect Volt, I'm thinking about building a > >reference voltage generator which would average the voltages generated > If you want to do it "right"

Re: [volt-nuts] The "averaging reference"

2014-12-18 Thread Poul-Henning Kamp
In message <5492f59e.8060...@free.fr>, Joel Setton writes: >In my search for the Perfect Volt, I'm thinking about building a >reference voltage generator which would average the voltages generated >by 8 or 10 REF102CP chips (with a simple resistor network), mounted in a >temperature-co

Re: [volt-nuts] The "averaging reference"

2014-12-18 Thread Andreas Jahn
Hello, I would expect a stability of around 10-15 ppm over one year after 6-12 months run in time. The reason is that with the plastic package all references will have about the same change in the order of 0.5ppm/% rH change. So assumption is that you have maximum 30% rH change over one year.

[volt-nuts] The "averaging reference"

2014-12-18 Thread Joel Setton
Folks, In my search for the Perfect Volt, I'm thinking about building a reference voltage generator which would average the voltages generated by 8 or 10 REF102CP chips (with a simple resistor network), mounted in a temperature-controlled box. Among all the experts on this list, does anyone ha