Re: [volt-nuts] Would you be concerned if the manufacturer does not have an uncertainty budget, so can't provide uncertainties in a calibration?

understand, it is maybe different here in Germany then, there are a number of labs with pretty low uncertainties who also support old gear adjustments. on the other hand, you have to know who you are working with for what gear. Otherwise you can have unpleasant surprises. in your case, if you

Re: [volt-nuts] Would you be concerned if the manufacturer does not have an uncertainty budget, so can't provide uncertainties in a calibration?

-a calibration certificate without uncertainsties is totally useless. in is not even a calibration. -I have never understood why people are so keen on getting things calibrated at Keysight. > Gesendet: Donnerstag, 19. April 2018 um 14:08 Uhr > Von: "Dr. David Kirkby"

Re: [volt-nuts] 3458A drift checking question

the manual defines a 4 hours warmup time. after tat the meter is supposed to be within spec. then the note 18 test can be started (ACAL and reading the cal constant). then it should be left on for a couple of days before a new acal is done, ideally as long as the note 18 specifies (7days iirc)

Re: [volt-nuts] Drifting 3458As

If you are confident that the 732A is stable to 0.1ppm then just run an acal afer a wek, and determnine what has driifted. Your A/D board, as can be seen with a drifty cal constant, or, els the A9 ref. Dont do a checl everyday. this hides information. > Gesendet: Freitag, 01. Dezember 2017

Re: [volt-nuts] Drifting 3458As

What you describe (A9 drift) would be the explanation. However question is how much you see. The A9 should not drift much in the intervals you talk about (days). Also, you should run the ACAL to determine the cal constant not several times a day but with several days inbetween, and then divide

Re: [volt-nuts] Get 10K resistor calibrated in UK

mine, since it was built in 1977, has drifted upwards by 1.6ppm. There is also a picture showing druft data of several SR104s on eevblog, but dont have the link handy. > Gesendet: Mittwoch, 29. November 2017 um 15:25 Uhr > Von: "Electronics and Books via volt-nuts" > An:

Re: [volt-nuts] Best way to measure micro Ohms

The question is what accuracy you need. The classical way to do that (achieving high accuracy) is to apply a known accurate current (say 10A) and measure the voltage drop accross the rod with a nanovoltmeter. As the piece of aluminum is isothermal you should not expect a big thermovoltage. You

Re: [volt-nuts] Fluke 732a concernes

Igor, I would actually ignore the 1V and 1.018V outputs. You can always determine their actual value using your 3458A in transfer mode against the 10V. The purpose of a voltage reference is not to be at exactly the nominal value all the time (requiring readjustment), but just to be close to

Re: [volt-nuts] PCBs with ceramic substrates

well, certain Rogers materials have an even higher surface resistance than PTFE, and are the preferred choice in that case. > Gesendet: Donnerstag, 06. April 2017 um 06:38 Uhr > Von: "Attila Kinali" > An: volt-nuts@febo.com > Betreff: [volt-nuts] PCBs with ceramic substrates

Re: [volt-nuts] Low-cost Josephson Junction Array

About two years ago I started an exercise to determine what it would take to build a kind of DIY JJ standard and also looked at certain detail technical aspects of designing/building what is reasonable doable. Baseline was 10V DC. It was clear that it would not be cheap, and I also looked at

Re: [volt-nuts] HP 3458A/HFL : looking for information/photos/fw

The value of the HFL is that by spec, it is better. So you can use its improved values in your uncertainty budget. If you do an upgrade yourself, you cannot rely on that. So you have to characterize your instrument after that. But you can as well do that with the standard meter as-is, and

Re: [volt-nuts] Thermal EMF - more results

so far so good. but what do we learn from this? the solder alloy is essentially irrelevant > Gesendet: Mittwoch, 06. Juli 2016 um 15:42 Uhr > Von: "Herbert Poetzl" > An: "Discussion of precise voltage measurement" > Betreff: Re: [volt-nuts] Thermal

Re: [volt-nuts] New scan of Solartron 7081 Service Manual is now available.

Dave, great thing, thanks! could you not also post to xdefs or ko4bb? I guess more popular these days. cheers > Gesendet: Dienstag, 14. Juni 2016 um 14:27 Uhr > Von: "David C. Partridge" > An: "'Discussion of precise voltage measurement'" >

Re: [volt-nuts] LTZ1000 project build

the issue of resistor drifts is mainly related to the amplifier (7 to 10V) gain resistors, the other resistor drifts do have a very limited impact on the output (see data sheet). > Gesendet: Freitag, 03. Juni 2016 um 23:47 Uhr > Von: "Lars Walenius" > An:

Re: [volt-nuts] ADA4522

not sure the TI filter circuitry, although very nice, is stable with the ADA4522. have not checked, but R2/C2 loop stabilizer may not work with ad4522. would require analysis/test, but positive result would sure make this a great reference buffer amp. if you do, would be nice if you let the

Re: [volt-nuts] ADA4522

Low frequency noise is very good, but is is high noise at about 800kHz (chopper) and above (possible artifacts). That should be filtered, depending on your application. What did you foresee to get rid of it, or would you accept it? Simple RC filter as indicated in the manual increases the

Re: [volt-nuts] Update on 7081 input / cable connector

well, are you sure that includes the bracket and so? I think I paid more than that about 1+ years ago. > Gesendet: Freitag, 18. März 2016 um 03:56 Uhr > Von: "Pete Lancashire" > An: "Discussion of precise voltage measurement" > Betreff:

Re: [volt-nuts] Low-cost voltage reference questions

Charles and group, another persons opinion: I guess the reference to the "standards" means those sold on ebay US. If so, I would think it is a false expectation this would meet 3ppm acc. guaranteed within a year. There is a lengthy chat in eevblog about it, in case you are not aware, and

Re: [volt-nuts] Low-cost voltage reference questions

There are many things to factor in. Drift of reference itself over time and temperature (399 is 1ppm/K worst case alone, over say 10K, i.e. 23C+/-5K). Drift of the gain setting resistor is critical (assuming you have an amp generating 10V out of the 399 output voltage). and so on. Also, you

Re: [volt-nuts] U150 1920-8937 Relay Driver for HP 34401A

at keysight directly, e.g. on stock at keysight germany, less than 20 euro. > Gesendet: Montag, 12. Oktober 2015 um 20:02 Uhr > Von: starb...@uplink.net > An: "Discussion of precise voltage measurement" > Betreff: [volt-nuts] U150 1920-8937 Relay Driver for HP 34401A > >

Re: [volt-nuts] Anyone know how to make stable inductors?

I did a quick and dirty check, using a standard wire DUT adapter with my (not calibrated) 4275 meter and 2x 100R and 1x 1000pf. According to the guide below, this should reslt in 10uH. Checked the parts allone with the meter before, all reasonably close to nominal. One end of the resistors

Re: [volt-nuts] Anyone know how to make stable inductors?

Thats a great document, and certainly is a supperior method than doing some DIY coils, provided very stable resistors and capacitors are used. Resistors is straightforward. As capacitors, mica glass is recommended. There are some NOS russian mica high rel capacitors available for little money.

Re: [volt-nuts] Test Leads

the best is really to use bare copper wires, such as used for wiring bells at home. does not look fancy, but low EMF. Re. the low EMF Pomona cables with 4mm plugs, when you insert them in their (Pomona's) low EMF binding terminals, the spring that activates the safty protection pushes them out

Re: [volt-nuts] Bls: Bls: How accurate is a fluke after 9 years

it is this resistor, in its z-foil version. they can be ordered from vpg distributors also in small qty (some may have a min. order value), lead time is usually pretty high. Gesendet: Montag, 18. Mai 2015 um 02:39 Uhr Von: Anton Moehammad via volt-nuts volt-nuts@febo.com An: Discussion of

Re: [volt-nuts] *WAY* too expensive for even Keysight to redesign

Hello, Your last statement actually could be a nice project in one of the well known blogs... I have thought about this as well. It should not be too complicated to do that. The core components the stability are defined through are not that many. ac current may be an issue though (I have seen

Re: [volt-nuts] Advise to Junior Member Regarding Acquisition of Fluke 5XXX Series Calibrator

A few things to keep in mind: - the 720A (and the 752A) are self-calibrating, i.e. you can (easily) calibrate it yourself before use. The 3458A, using its external artifact self-cal procedure based on only 10v and 10k, requires a performance verification therafter (at least every second time,

Re: [volt-nuts] AC voltage standards.

these instruments are painfull to use, complex measurement procedures and pretty unstable (if you want to use their ppm resolution). I spend hours and hours calibrating a set. lots of data available from standards labs. what I would recommend is a ballantine 1605A. easy to use, very precise,

Re: [volt-nuts] Calibration of voltage standards

the 3458A is very well suited as a nullmeter (there e.g. also is an appnote from Fluke on this). I have checked this against other meters such as the e.g. the keithley 155 and 34420A, and for my setup (Fluke 732A, Datron 4910 and others) I have the least problems with noise, common mode issues

Re: [volt-nuts] Checking an LCR meter

I have a smiliar issue, so interesting to read this. Mine is related to older gear like 4192a and 4275A meters which I am using. All these old meters, if properly adjusted an calibrated, are very good meters, you can repair them yourself, and are very cost efficient (what did you pay for our

Re: [volt-nuts] plastic caps on 3458A reference board

this would be over-engineered, unless you have a lot of spare time or want to do this for fun. If you use plastic supports as they were used when these TO packages were common (these supports should still be available, they surround all pins and quality plastics were standard) and use any cap

Re: [volt-nuts] Old HP3458A - SN: 2823A 03939

hi the EPROMs are in sockets, no soldering needed. but again, buying a precision instrument but reprogramming cal data that is years old does not make any sense. unless of course if you are just a collector and do not use its accuracy. adrian Gesendet: Dienstag, 07. Oktober 2014 um 16:35 Uhr

Re: [volt-nuts] Old HP3458A - SN: 2823A 03939

well, I do that with my references if they cannot be adjusted reasonably such as the 732a. but for meters and calibrators I do not. achievieng high precison with such an instrument then means you still need to characterize it (i.e. calibrate, and not adjust it, doesnt save money essentially)

Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left

folks, does anybody know the difference in specs between a 4920M and the standard 4920. No data on the web. thanks Gesendet: Sonntag, 31. August 2014 um 23:41 Uhr Von: Charles Black cbl...@centurytel.net An: Discussion of precise voltage measurement volt-nuts@febo.com Betreff: Re:

[volt-nuts] Using a DVM to adjust a 752a divider

Resend as it did not go to the group (please also see my question at the end of my mail): mitch, you bring up a good point. I did not know the document, thanks for sharing. it inspired me to do some measurements, thats why it took a while to respond. the results were quite surprising to me.

Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left

thanks, I would welcome comments on calibration too. Gesendet: Dienstag, 02. September 2014 um 12:23 Uhr Von: Stephen Grady grady.st...@gmail.com An: 'Discussion of precise voltage measurement' volt-nuts@febo.com Betreff: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day

Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left

charlie, you can expand these tvcs by range resistors to work as higher voltage tvcs. if you do it right (rf-type setup) you can work up to a couple hundred khz with just minor additional error beyond its error in its orgininal voltage range. need to calibrate them however. using an attenuator

Re: [volt-nuts] 732A and Prologix received

I do fully agree with you. this has become, to a big extent, an academic debate. it may be relavant if the resolution needs to be in the nv-range, such as working with josephson-elements. I guess nobody in this group here is. to your question, yes, the 34420a and the 2182 nanovolt meters use

Re: [volt-nuts] AC calibration

what nist means is that a precision meter is not considered a standard. you always measure against a true standard (732a, esi sr104...). nist does not mean that as part of doing equipment calibration a 3458a cannot be used as aid. also keep in mind nist has a different approach than a cal lab,

Re: [volt-nuts] 732A and Prologix received

well, what you do is to measure the stability of the 3458a. 1ppm drift though sounds much as overall short term average variation if your temperature is stable and your 3458a is always on. probably the temp is not stable, and that is what you see, amongst potentially some other smaller drifts

Re: [volt-nuts] 732A and Prologix received

hi randy, the specified drift of the 3458a over your 38.1 to 40.3 (about 1k) is 1ppm +/- allone in the 10v range. thats 10uv. in other ranges its worse. unless your 732a is very bad (very unlikely), you measure mostly the 3458a temp. drift. 1000nplc and 100 readings average do not make sense in

Re: [volt-nuts] AC calibration

Dave, the title is: Thermal Voltage Converters and Comparator for Very Accurate AC Voltage Measurements by E.S.Williams. Adrian Gesendet: Montag, 25. August 2014 um 19:32 Uhr Von: Dave M dgmin...@mediacombb.net An: Discussion of precise voltage measurement volt-nuts@febo.com Betreff: Re:

Re: [volt-nuts] 732A and Prologix received

hi randy, just for curiosity, why doing 100 measurements at nplc 1000. is this to sample a changing value? when i am doing 10 measurements from a stable signal at nplc 100 (only there many subsequent measuremnts with statistics make sense) I am already getting a stanard deviation below 0.1ppm.

Re: [volt-nuts] 732A and Prologix received

I have used the pomona spades, mainly to interface the low emf pomona banana cables to binding posts. I have stopped this, reasons being, they are large and worse, that the pomona spring loaded insulation tube that covers the banana plug conductor uses such a strong spring that slowly the plug

Re: [volt-nuts] 732A and Prologix received

well, your last point is the issue, how can you have a temperature difference within a few microns of material in said connections. theory is one thing, but in reality it does not happen due to the givens of the setup. therefore in practice it is irrelevant if the wire is silver or gold plated

Re: [volt-nuts] AC calibration

fred, generally you raise a good point, I had the same issue of calibrating an ac voltage to a high level of accuracy. you need this e.g. to validate the self.cal of a 3458a or other precison stuff like the 8506a0. what i would recommend to do if you want to keep costs down is: in a nutshell,

Re: [volt-nuts] 732A and Prologix received

Randy, I have replaced batteries in two units so far, which I bought on ebay (6V) and they fitted absolutelly perfect, no need to rework an metal and there was o isue with shortages. So there certainly are standard 6V batteries that fit without mods. I always try to keep things in original

Re: [volt-nuts] 732A drift

Randy, that is strange. two things come in mind that might be worth checking. first, is the mains frequency setting of the 3458a set to 60Hz (I assume you are in the US)? this is important to suppress mains ac disturbing the measurement. secondly, have you connected guard? tsp cables would be

Re: [volt-nuts] What's All This Low Thermal EMF Test Lead Stuff?

if you buy a voltage source that is cal'ed to 6ppm you do not end uop with a factor of 10 (60ppm). the fatcor of 10 is often used to be on the safe side, but in high percision cals 10 is not achievable anyways. some mil standards call for 4, but what you should do is to analyze the error

Re: [volt-nuts] Fluke 732A themistor reading

well, re. the resistor, question is how stable it is, not so much absolute value. if not very good, your 3458a may be more stable that your reference. vpg hermetic foil 4 wire resistors are very stable (1ppm pa) and are cheap (50usd). re the wire, you should use twisted shielded pair. there are

Re: [volt-nuts] HP-419 and Fluke 845 Modifications

I have no personal experience with the 845, however am using the keithley 155 as nullmeter fo precision calibration. I had used the 182-M (a low noise version of the 182) and other digital gear before such as the 2182, and the 155 performs very well, is easy to use with not much noise and very

Re: [volt-nuts] Matched resistors

yes, charge injection is an issue with all these switches and these also vary, in other words are somewhat unpredictable. now some of this may be compensated by a bigger c, but there are natural limits too. so for a production unit to sell, this would probably be a killer, but also for

Re: [volt-nuts] Matched resistors

and yes, I forgot: only down-dividing of course, so to reach 10V, two LTZ1000 would be needed in series. advantage is that noise statistically is reduced by factor of about 1.4. formally also applies to drift. Gesendet: Montag, 21. Juli 2014 um 20:28 Uhr Von: Bob Smither smit...@c-c-i.com

Re: [volt-nuts] AC Voltage Measurement Standards

I have a set of 7 TVCs, from 1 to 100V. having them all calibrated externally is just too expensive. There is no doubt that having all 7 TVCs calibrated at NIST or PTB, wherever you are, is much more precise, I will just not spend it and live with the accuracy I get. As source I am using a

Re: [volt-nuts] AC Voltage Measurement Standards

in a nutshell, what i am doing is that I first establish the dc (+/-) output of the ref. TVC at nominal and then determine the ac voltage from a precision, highly linear (datron 4808) ac source that generates that default output voltage at the key frequencies. that establishes a set of ac

Re: [volt-nuts] Buying HP-3458A

well, some time ago, when I bought my first 3458A, I looked into the data sheet of the 3458a and I figured that the basic accuracy of their standards is not terribly good. 2ppm each, you need to add this to all their specs. dont get me wrong, for most it is really sufficient, but as we are all

[volt-nuts] transfer accuracy

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