Calibratory D-105 DC Precision Voltage Reference Standard

[Jay_Diddy_B]

Hi,

I did a little more analysis on this circuit:



The sensitivity of the trim pot, R5,  is about 42 ppm per turn or 8.5 degrees per ppm.

Jay_Diddy_B

[babysitter]

@Jay_Diddy_B: Thank you for your analysis, data gathering and drawing the (mostly) obvious

I would like to know what happens when you remove this piece of cooper tape vs no cooper tape, maybe even versus sticking the thermistor to the case or socket by locite or wire springyness.

I wouldn't expect the cooper tape to work that well as a thermal bridge as it is so thin and long(source: gut feeling), but maybe its just the right amount. Are you sure it doesn't come lose ever, it looks dubious to me (source: Our cooper tape might when used like this)?

As a heat spreader it might help to improve thermal coupling the surrounding resistors and the trimmer, however. Put those experiments after the first few long-time runs. One needs patience to analyze voltage standards.

And for those people that are strict against perfboard: Give it a chance, dont't discount it completely! Holes store zero humidity , although it is additional surface that allows gas exchange. They are excellent thermal and electrical insulator, even when the cooper-to cooper interfaces of the soldering eyes are closer. And the holes provides the stress relief for the package that so many consider very imporant.

@Calibratory: Measurements will show if it keeps the promises of marketing. At the moment it has a "very optimistic datasheet" that needs to be proven or fixed. Your claims sound a lot like those of audiophools, sorry, product might come out better than those, but still, you degraded trust in you by this bullshit. Recovery is possible.

You might learn a lot about your reference here. If you realize something you learn here to advance your product, like repositioning of the thermistor closer to the case, stopping the useage of fairy tales or not basing your marketing promises on nulling to a single reference standard with questionable state even when it is a fluke,consider paying consulting fees. Because you are cool and we are cool . Please.

[Awesome14]

The photos of the D-105 DC posted in this discussion thread are not representative of a typical unit. Also, members here may disagree, but the perf board is the best for this application. It allows convection airflow to stabilize the unit faster and keep it more stable, and it also reduces hysteresis because of the large number of expansion and contraction relief points. If you disagree, please present some evidence to support your point rather than attacking me as a person.

If you cannot keep yourself from attacking me as a person, please get help and then reply. I have presented a +-2ppm voltage reference to support my thesis. Given that a perf board is going to be used, and bare component leads are going to be soldered to pins instead of solder pads, it's just not going to look as pretty as if there were solder pads.

But it works. Yes, the devices might all develop idiosyncratic characteristics, but I contend that these will not throw the device off so that the +-2ppm error-limit is breeched. And to say that these design features preclude manufacture of the device is simply arrogance!

Some members claimed I should be ashamed at the soldering on the board. It really isn't that bad for a perf board. Some didn't like the 4 cables connecting the board to the terminals, claiming it could induce negative characteristics into the output signal. But, again, I have presented a +-2ppm voltage reference to support my implicit claim, while the critics have presented no evidence to support their claims condemning my cable setup.

The device is not intended to be disassembled. That is clear by the seal over the screws. Some members have indicated to me that the design is insane for that very reason: because the device cannot be disassembled and reassembled by the user. I disagree. There are some trade-offs that must be made in order to fit a +-2ppm reference into an ultra-miniature package that can be carried in a pants pocket. The package also must endure environmental extremes, shipping shock, low atmospheric pressure found in cargo planes, all the while maintaining calibration in a powered-down state.

The units are sealed air-tight to prevent large internal relative-humidity changes. Piercing the anti-tamper seal breaks the air-tight seal. Am I to be faulted because others break a seal that is obviously not to be tampered with? NO! I cannot be blamed for design features that collectively produce a +-2ppm voltage reference for under 100.00USD. Those who ignore right reason in their quests are to blame for whatever they get! 

Saying that the design is insane, because the units cannot be disassembled and reassembled by the user, is like saying "His face hit my fist." It's contrived nonsense! The user is to blame for ignoring right reason. I have presented a +-2ppm reference to support my claim. There is evidence presented by other members that support their claims. I don't know what else the members here could want to encourage a positive—or at least neutral—stance toward the D-105 DC and it's capabilities.

I commend those who have held open minds, awaiting results. I don't know what the problem is with potential for long-term drift. I've done something remarkable. But one thing I haven't done is: eliminate the need for periodic calibration.

I've read in this discussion thread that eBay is wrought with questionable claims regarding voltage standards. It really isn't. I'm called overly optimistic for my item description. I think honest would be the proper word.

I've been accused of using hokum terms to describe concepts that have no label, such as: thermoelectric-effect damping. On this board I fell like everywhere I step there's going to be a turd. I am not particularly sociable or friendly, but I am respectful toward others. If you dish it out, be prepared to get some of it back!

I'm reminded of the member who made the sarcastic comment questioning my worth as a person, in a rude way. When his own words were used against him, he went off in a tirade. I have enough respect for others that I'm willing to reflect back honestly to them what I see.

Due to my abilities, both physical and intellectual, I have endured the bitterness of others my whole life. What perplexes my peers seems intuitively obvious to me. Many others have been outright livid at the ease with which I bring my thoughts to fulfillment.

Among other things, I'm a computer programmer/analyst/consultant. During my first two weeks of intro programming class I purchased a programming  book and became a published software author. Several weeks later I established myself as a computer consultant.

I thought the instructor would be happy to have a good student. But he told the entire class that I was simply arrogant to parade my abilities. So, due to an endless litany of being bashed for my capabilities, I might have a bit of a chip on my shoulder. Please bear with me.

I am a very capable individual. I have 1.4 million readers in 155 nations! I must remain anonymous, because I've experienced 15 murder attempts in the last 3 years, all because of what I write.

I'd like the help of the people on this board to confirm my findings, and to discover hidden weaknesses in my design. To the members who have disassembled their units I say, contact me for free replacements in exchange for the ones that were opened. As long as there is a reasonable output value, the return will be excepted. I will do this for up to 2 members of EEVBlog.

My comment made privately to an eBay user, which was then made public in an attempt to smear me, mentions magic.  I believe there was a misunderstanding. Appears to be magic means: it looks like magic, because nothing quite like this has been seen before, so it challenges our concept of what is possible—something like a 2-foot tall front-end loader that can lift a skyscraper—but we both know reality is governed by inflexible laws beyond the capability of mankind to alter.

It does NOT mean: I've evaluated all possibilities, and I've discovered the device is controlled by magic! But I suppose it is the engineer's place to first doubt, imagine the worst case, and then work toward a solution.

I felt like I had to defend myself and my invention. Now, I'd like the thread subscribers to just do whatever you do, and discover what you can. But bear in mind that I have never had a complaint regarding my voltage standards sold on eBay until I came here, which was that the solder is messy.

I've fielded messages from uninformed critics berating me for deceiving the amateur-electronics community in such an insidious way. I've learned that they all go silent when exposed to the light of truth.

And, finally, few people understand the desire to do good for the sake of itself. I'm not concerned by finances, because I have the money I need, and it's important for me to set an example for others: money will not buy what everyone truly desires. If I showed you the AC battery that never requires charging, that runs forever, you would not believe, because it's against the laws of physics. But it isn't if the energy is coming from somewhere; ambient energy coherently converted into a usable form.       

[Zucca]

I've experienced 15 murder attempts in the last 3 years, all because of what I write.

Wow, that´s scary. If you wrote the truth you should not be afraid. Nobody can hide the truth. They already lost the battle.

I have presented a +-2ppm voltage reference to support my implicit claim, while the critics have presented no evidence to support their claims condemning my cable setup. 

EEVBlog members are the most passionate electronic people I found, I fell like home here. Surely that same passion will drive them to take you product and provide the evidences to see if your claim is true or not (as already mentioned by someone before). To be honest with you I did not see a NIST certification from a proper Cal Lab either and togheter with the pictures of your board, please do not be offended, but I think it is legitimate to have some doubts. Of course we need evidences all the rest is just bla bla . In God we trust, the others bring data please.

but the perf board is the best for this application. It allows convection airflow to stabilize the unit faster and keep it more stable, and it also reduces hysteresis because of the large number of expansion and contraction relief points. If you disagree, please present some evidence to support your point rather than attacking me as a person.       

Imagine you could have the possibility to place the VIA holes where you want.
Imagine you could move the tracks on the PCB and build the relief points where you want.
Good news for you: it is possible!

...I'm a computer programmer/analyst/consultant...
...Due to my abilities, both physical and intellectual...
...I am a very capable individual...

Oh you can also use the computer so well, this is perfect! I am now begging you on my knees: PLEASE USE A PCB CAD and design a proper board.
What a pity, with your capable brain you have the potential to improve your actual poduct a LOT! Not interested to lower the +-2ppm? Since you don´t need money, you could really spread the beauty of your project anywhere in this planet! Unleash your potential!

A friendly open mind regard,

[janaf]

As I understand, there are a few of these out there being measured by others than Awesome14. I'll just wait a few months or to see what these measurements show, including transport, humidity, temperature, aging. I hope to se measurements on a handful to get an idea of what's "typical" and what the spread is. Even if the explanations are eccentric and used the components and make me skeptical, claimed results could still be valid.

The price seems to has gone up to US $157.95 ....

[janaf]

Off topic: Actually, water DOES boil at 273.15 K or at least exists as steam. That's precisely what the triple point is about. The key is pressure, i.e. conditions have to be absolute vacuum from any other gas.

I have used the so called triple cells. They are hermetically sealed coaxial vessels with water only, no air. They look like a small glass thermos / Dewar. The water is where the vacuum would be in a regular thermos.

You freeze the triple cell by circulating very cold liquid through the center cavity. We used pure alcohol at minus 40C. You have to do it nice and slow. If the water turns to solid, the glass burst at you wasted about $2000. But when it's right, you get a thin ice layer and a water / ice slurry, while the "vaccum" is actually filled with water steam. This mix can physically exist at one temperature and defines 273.16 K (0.01C) in the ITS-90 temperature standard.

From the Fluke web site:

"Must-have, primary temperature standards

• Easy-to-use, inexpensive standard with uncertainty better than ± 0.0001 °C
• Isotopic composition of Vienna Standard Mean Ocean Water

The triple point of water (TPW) is not only the most accurate and fundamental temperature standard available, it’s also one of the least expensive and simplest to use."

http://us.flukecal.com/products/temperature-calibration/its-90-temperature-standards/5901-triple-point-water-cells-1

Also, "water boils at..." and "water freezes at..." are statements subject to all sorts of standardized conditions (absolute purity, standard atmospheric pressure, stable equilibrium). In any experiment you perform at home, water is unlikely to boil at 273.15 K.

even if you have perfec at standard conditions the boiling point of the water is not anymore 100,000 degrees like it was previously because of the latest temperature scale doesn't use it as a defining point like earlier ipts68 did. 

Point noted. However, water is unlikely to boil at 273.15 K for the more fundamental reason that this is actually the freezing point of water... 

[Dr. Frank]

The 732A has an actual output of 10.00000471 when compared to a 732B sent from Fluke Calibration. Fluke assigns output values of their 732Bs  based on their superconducting, cryogenic Josephson Effect standard, which is accurate to 18 decimal places. The error of the 732A is taken into account. We only track the error on the 732A. No turning of the pots. That was done 04/14. The maximum drift of a working 732A is 0.6ppm/month. That was measured by a 48 hour test, and the 732A is within spec., and it's within calibration. So, the uncertainty is 0.6ppm*10months=6ppm max, but probably less. Given that the 732A has had no observable change since last calibration, it is probably less than 6ppm uncertainty. 


.... claimed stability of 0.15ppm/°C

 that is the mean s=10 from 16-26C.


... 1.5ppm/1kHrs in operation

the long-term drift is stated as can be expected, which is a bit softer than will be.

Hello Awesome14,

these additional information are to my opinion much more reputable.

I think, it is not necessary to have such a long and tiring text on your ebay offer, which made the impression on me of a market crier.

I would recommend, that you bring the specification of your device in a more familiar form, only using the important parameters with typical and maximum limits. Latter ones are really missing, or misleading in your current specification and description.

Then it will be obvious, that your product really delivers the (quite good, but not stellar) performance you intended, and what everybody who is trained in electronics / metrology can expect from such a crude setup, and also without the need to refer to any of these 'miraculous' or whatever features or treatments.

It's now obvious, that there are no such, and the buyer only gets what everybody can see in the pictures.

Your device and the trimming of output and T.C. is really very similar to the Geller Lab device, and I think it therefore may perform similar, despite your design.
 
Additional questions:
- How often do you calibrate your 732A, and do you have a history?
- What denotes "s=10"?
Do you mean, that you measured the averaged T.C. by taking 10 output measurements between 16..26°C, and then really trimmed to 0.15ppm/K?
- Did you ever measure these 1.5ppm/1000hrs on one or on a set of devices, over a longer period of time?


OK, let's see, what we can summarize up to now from your information:


uncertainty of Fluke 732B compared to NIST / SI: 0.3ppm, 30 days / 1.6ppm, 1yr. (which one?)
uncertainty of 732A output, compared to 732B: 0.1ppm transfer, using HP3458A
stability of 732A: 0.6ppm/ mo. => 6ppm after 10 months (maximum value)
typical uncertainty maybe < 1ppm, if enough history is available, to predict the timely drift of the 732A
initial uncertainty of D-105 compared to 732A: 0.1ppm transfer accuracy, using HP3458A

Therefore, if I sum up all these uncertainties, optimistically taking the best 732B uncertainty, 30d.:

uncertainty of D-105 to NIST: 1.5ppm typical , 6.5 ppm maximum

Therefore, your claim of +/-2ppm (accuracy? uncertainty?) is reasonable, when you'd declare that as a typical value.
Here's room for improvement, if you use the history.



T.C. = 0.15ppm/K , maybe average T.C. over 16..26°C (box method), max. 2.5ppm/K (from REF102C datasheet)
=> no precise information about trimming or measuring the T.C.

realistic again is the <1ppm/K max., which Geller labs specified, because the design is similar.
Geller uses high grade, low T.C.  resistors, D-105 uses inferior thin film resistors.


long term stability:
1.5ppm/1000hrs. typical, but not proven yet

more realistic is typically 20ppm/1000hrs. ; typ. 5ppm/1000hrs after 168hrs. op. stabilization


Well, if you could provide some more details about your T.C. trimming and maybe long term monitoring,
this could really make up a quite good reference.

Frank

[MadTux]

I am a very capable individual. I have 1.4 million readers in 155 nations! I must remain anonymous, because I've experienced 15 murder attempts in the last 3 years, all because of what I write.       

Must be a scary as hell. Where did you live to get assassinated that often? North Korea? Syria or South Africa 20 years ago? Wanna hear some cool stories, please.

[saturation]

Wow  .  Things have gotten pretty exciting here in a week  .  I am with Dr. Franks' posts, we really need to test the performance claims before all else.  While criticizing the construction is fair for academics' sake, it becomes moot if the device does perform as stated or even close to it.  Why change what works?  The bigger question then becomes why.  Even if drift is much shorter term, say at 30-90 days or so, it would still be cheaper shipping this device around than a Fluke 731b device as a transfer reference.  Owners can brainstorm thereafter improvements to extended long term stability, but we are not even there yet to consider it.

If a D105 made its way to eevblog labs, having the good folks at TrioSmartCal lab give it a workout would be very interesting.

[Dr. Frank]

DiligentMinds,
Again, you're on the wrong trigger.

I think, this source has been demystified, and its performance turns out to be quite reasonable,similar to the Gellers ref., which also used a plastic case.

Neither of both refs claim (in the end) to be as good as a 732X..and also not as good as ovenized LTZs Therefore, calm down and wait what this ref really shows in the lab.

Frank

[quarks]

Hello Dr. Frank,

because I have several Geller SVR I can confirm that they came with ceramic package AD587LQ.
https://www.eevblog.com/forum/testgear/geller-labs-svr-and-svr-t/msg271788/#msg271788

Bye
quarks

[Dr. Frank]

Well, then the description on Joe Gellers site is different.
Frank

[paulie]

I have some suggestions for improving your reference

Me too. Use precision components that cost at least an order of magnitude more. Preferably 0.00001% tolerance and gold plate where possible. Actually solid gold for the case would be nice to take advantage of superior thermal characteristics-.

And while you are at it cut price in half. Or better still $25 would be nice so I could handle it with one weeks allowance. And free shipping like all the Chinese sellers.

Just my 2 cents.

[quarks]

All my SVR and SVR-T came with ceramic chip.
The SVR is a great transfer standard and I would buy it anytime again.
To bad it is not available anymore.

[TunerSandwich]

The photos of the D-105 DC posted in this discussion thread are not representative of a typical unit.

Yes, the devices might all develop idiosyncratic characteristics...

And to say that these design features preclude manufacture of the device is simply arrogance!

The units are sealed air-tight to prevent large internal relative-humidity changes. Piercing the anti-tamper seal breaks the air-tight seal. Am I to be faulted because others break a seal that is obviously not to be tampered with?

It's contrived nonsense! The user is to blame for ignoring right reason.

I don't know what the problem is with potential for long-term drift.

I've done something remarkable.

I've read in this discussion thread that eBay is wrought with questionable claims regarding voltage standards. It really isn't.

On this board I fell like everywhere I step there's going to be a turd. I am not particularly sociable or friendly, but I am respectful toward others.

Due to my abilities, both physical and intellectual, I have endured the bitterness of others my whole life. What perplexes my peers seems intuitively obvious to me. Many others have been outright livid at the ease with which I bring my thoughts to fulfillment.

Among other things, I'm a computer programmer/analyst/consultant. During my first two weeks of intro programming class I purchased a programming  book and became a published software author. Several weeks later I established myself as a computer consultant.

I thought the instructor would be happy to have a good student. But he told the entire class that I was simply arrogant to parade my abilities. So, due to an endless litany of being bashed for my capabilities, I might have a bit of a chip on my shoulder. Please bear with me.

I am a very capable individual. I have 1.4 million readers in 155 nations! I must remain anonymous, because I've experienced 15 murder attempts in the last 3 years, all because of what I write.

I will do this for up to 2 members of EEVBlog.

My comment made privately to an eBay user, which was then made public in an attempt to smear me, mentions magic.  I believe there was a misunderstanding. Appears to be magic means: it looks like magic, because nothing quite like this has been seen before, so it challenges our concept of what is possible—something like a 2-foot tall front-end loader that can lift a skyscraper—but we both know reality is governed by inflexible laws beyond the capability of mankind to alter.

It does NOT mean: I've evaluated all possibilities....

I've fielded messages from uninformed critics berating me for deceiving the amateur-electronics community in such an insidious way. I've learned that they all go silent when exposed to the light of truth.

And, finally, few people understand the desire to do good for the sake of itself. I'm not concerned by finances, because I have the money I need, and it's important for me to set an example for others: money will not buy what everyone truly desires. If I showed you the AC battery that never requires charging, that runs forever, you would not believe, because it's against the laws of physics. But it isn't if the energy is coming from somewhere; ambient energy coherently converted into a usable form.       

Seriously?  And you are calling others arrogant? 

I'm sorry but I simply don't see where you have done anything "remarkable".....in fact I see a rather un-remarkable attempt at self marketing an average "voltage standard"....with claims that you have somehow cracked some great physics mystery....

If you keep experiencing hostility from others....throughout your life....maybe it's time to take a step back and realize the problem isn't everyone else 

P.S.  "sealed" is a total embellishment....your package is NOT hermetically sealed, nor is the inside of the enclosure a vacuum....I'm sorry, but your claims are very over the top....there is nothing remarkable or special about your device....although I think the REF102C is an excellent and inexpensive ref IC chip....+/- 2ppm (which is totally unfounded over time) is not "remarkable" 

[691175002]

Why do these guys always have to sound crazy?  Unverifiable anecdotes, pleas to authority, and meaningless technobabble just make you look defensive and uneducated.

Provide logical rationale for the design decisions that have been made and everyone is happy.

[richiem]

My Geller SVR is a plastic AD package. Hadn't hooked it up in quite a few years, so just got it out and it's stabilizing with 15V supply from a linear regulated bench supply.

[TunerSandwich]

I don't see how following a simple applications schematic is in any way cutting edge.....I simply don't see anything out of the ordinary (other than somewhat shoddy construction), and when confronted with that issue, the maker says "it's a big secret".  Really?  What is so special or secretive about a monolithic REF IC? 

Hell we have all seen the guts of a Fluke standard....and it's a far far far cry above and beyond the $100 ebay special....and even that isn't "remarkable" or "ground breaking"......nor is it "magic" nor does it do anything that can't be significantly bettered......it simply follows an accepted standard for producing reasonably low drift/stable transfer standards.....it's not magic, and it's not super science.....it's basic electronics engineering....given Flukes resources and engineering prowess, i highly doubt any of us here, acting independently are going to best their efforts and "revolutionize" any facet of their already acceptable design.....and it's surer than shit not going to happen at a $100 per unit cost basis.....

I found this whole topic quite amusing at first, but now it has crossed the line into complete and total insanity....conspiracy theories about death threats.....claiming mental superiority over other engineers....claims of cracking mystical boundaries of physics the rest of us are "too dumb to understand"....etc etc etc.....

this shit is just plain bonkers.....but wonderfully entertaining.....I can't wait to hear all about the death threats and "assassination attempts" 

[rx8pilot]

The design was a gift to me, and I'm passing it on.

uhhhhhh, I thought you invented it. Or was it given to you as a gift? Or do you mean a gift from on high?

[richiem]

I'm trying to get my head around where all the snarkiness is coming from. I've always thought of the EEV blog members as pretty substantial and serious folks who are generally even-tempered and polite. So I'm guessing there has to be a lot of life-stress in this small community for such uncivil comments to be on display. At age 75, I've tried to get past all that, and I recommend some quiet time for the members here -- a nap might serve....

[Andy Watson]

If I showed you the AC battery that never requires charging, that runs forever, you would not believe, ...       

At least you've got one thing right!

[rx8pilot]

I'm trying to get my head around where all the snarkiness is coming from. I've always thought of the EEV blog members as pretty substantial and serious folks who are generally even-tempered and polite. So I'm guessing there has to be a lot of life-stress in this small community for such uncivil comments to be on display. At age 75, I've tried to get past all that, and I recommend some quiet time for the members here -- a nap might serve....

I have seen rather civil behavior considering there is someone that is clearly trying to discredit the collective intelligence of everyone here. Mysterious scientific background and apparently some sort of rebel political writer that is under constant threat of assassination. Pseudo-science breakthroughs with not even the slightest bit of backup. This is a forum, not a show for someone to create a bizarre alter-ego of who they hope to be.

If any person was even a fraction of the claimed intelligence -  why would they sell a box with 4 hours of labor plus components for $99 on eBay? This is a 14 year old kid making parts in his dads basement. The ultra-smart distinguished scientist chose the name "Awesome14". Ok. got it.

[EEVblog]

I am a very capable individual. I have 1.4 million readers in 155 nations! I must remain anonymous, because I've experienced 15 murder attempts in the last 3 years, all because of what I write.

Care to share with us what you have written that garnered 1.4m readers and 15 murder attempts?
After all, it is public, right?
Perhaps you'll even gain some more readers...

[TunerSandwich]

I'm trying to get my head around where all the snarkiness is coming from. I've always thought of the EEV blog members as pretty substantial and serious folks who are generally even-tempered and polite. So I'm guessing there has to be a lot of life-stress in this small community for such uncivil comments to be on display. At age 75, I've tried to get past all that, and I recommend some quiet time for the members here -- a nap might serve....

I have noticed quite the opposite...also isn't this statement (of yours) a bit "snarky"  " I recommend some quiet time for the members here -- a nap might serve...."   

also "At age 75, I've tried to get past all that"   I don't see see it....if one was past all that they wouldn't be handing down their own judgments? 

I think most of the statements here are quite reasonable, in light of the astounding, hostile and un-scientific claims by the maker of this "standard".  Pile the borderline "insane" statements of mental superiority, death threats and assassination attempts, and I am surprised things are "civil" at all.....

This gentleman basically came on here and made wild and counter-intuitive claims, and then tried to talk down to everyone here (that didn't agree 100% with him) and yet people are still trying to offer suggestions on how to improve his design....and possibly deliver a more marketable and profitable product. 

I also see some fair bench evaluation attempts....DESPITE the makers hostility and general attitude of superiority.  I think this community has done a somewhat commendable job of trying to provide an UN-biased viewpoint of the gentlemans device. 

I would have expected a much "harsher" hand slapping than has been presented.....I doubt any "professional" product review would be so kind....

I guess we all have our own biases and viewpoints though 

[TunerSandwich]

The design was a gift to me, and I'm passing it on.

uhhhhhh, I thought you invented it. Or was it given to you as a gift? Or do you mean a gift from on high?

It seems to me it was a gift from Ti application engineers.....who probably absorbed and passed on that gift from an applications engineer at Burr-Brown