Calibratory D-105 DC Precision Voltage Reference Standard

[paulie]

I would love to see technical discussion but don't think there will much forthcoming from this crowd. Basically all units reviewed performed much better than advertised but most here just didn't like the "look" of it and enraged by the sellers reluctance to kow tow.

Somewhat reminiscent of Joseph Priestly. Not only was his house burned down by a mob but his church too. Right to the ground. Ironically he was the discoverer of oxygen in a world of phlogiston believers.

http://en.wikipedia.org/wiki/Priestley_Riots

[Terabyte2007]

I would love to see technical discussion but don't think there will much forthcoming from this crowd. Basically all units reviewed performed much better than advertised but most here just didn't like the "look" of it and enraged by the sellers reluctance to kow tow.

Somewhat reminiscent of Joseph Priestly. Not only was his house burned down by a mob but his church too. Right to the ground. Ironically he was the discoverer of oxygen in a world of phlogiston believers.

Well, let's not jump to conclusions yet on the D105. I have not yet completed the long term testing. Also, if Awesome14 would have just stuck to the technical aspects of the requests instead of getting all fire and brimstone then the conversation would have gone in a different direction. There are always going to be people that disagree with you and even criticize you, but you have to be professional and let it roll on by. This did not happen, just the opposite did! It really is all about being a professional, do you think Extech or Uni-T get all bent if someone hammers their product? Absolutely not, they try and improve it or fix the problem. It was hopeful for a while that this would be a possibility with Awsome14 and his product and it would have been very cool to be part of helping make a product better but, well, we all see how this turned out!

[alhoop]

Ok I 'm in need of a reasonably priced accurate voltage standard. How many of you goobers have one for sale
comparable to what Awesome14 offers?

Al

[The Doktor]

I don't think anyone here sells a standard ATM. Try www.voltagestandard.com , they have several models. Well made and make no unreasonable claims. Sadly they don't include any vampires with your purchase, you need Mr. Awesome for that 

Ed

[alhoop]

I don't think anyone here sells a standard ATM. Try www.voltagestandard.com , they have several models. Well made and make no unreasonable claims. Sadly they don't include any vampires with your purchase, you need Mr. Awesome for that 

Ed

Thanks Ed.
Those use batteries for the voltage source. Is there an advantage to batteries over a bench supply?
I'm a hobbyist and need something to check my personal meters and scopes. I also repair and sell the Tektronix 200 series
oscilloscopes on the bay and would like to have a means to check them also. I have tried the Tektronix PG506.

PS: Just purchased the DMMCheck Plus.

DiligentMinds:
"goober' was in reference to the poster of reply #57 of this thread.
An 'attack' on Awesome14 before he had ever posted here.

Al

[lowimpedance]

Sooo.. that means everyone else are also 'goobers' ??. 
What definition are you referring to ?.

[timb]

Sooo.. that means everyone else are also 'goobers' ??. 
What definition are you referring to ?.

I was the one who "attacked" him by calling him a goober. It means, "an unsophisticated person; a yokel," to quote OEAD. It's an old term used in the southern US.

Common usage is that of a lighthearted insult. Akin to schmuck perhaps? (Which I just found out originated from the Yiddish word for penis! TMYK)


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[branadic]

Remember that several CERDIP models of AD587 are available:

Model   Initial Error   Temperature Coefficient   Temperature Range
AD587JQ   10 mV   20 ppm/°C   0°C to +70°C
AD587KQ   5 mV   10 ppm/°C   0°C to +70°C
AD587LQ   5 mV   5 ppm/°C   0°C to +70°C
AD587SQ   10 mV   20 ppm/°C   –55°C to +125°C
AD587TQ   10 mV   10 ppm/°C   –55°C to +125°C
AD587UQ   5 mV   5 ppm/°C   –55°C to +125°C

Some of the are available at digikey and ebay.

[lowimpedance]

Sooo.. that means everyone else are also 'goobers' ??. 
What definition are you referring to ?.

I was the one who "attacked" him by calling him a goober. It means, "an unsophisticated person; a yokel," to quote OEAD. It's an old term used in the southern US.

Common usage is that of a lighthearted insult. Akin to schmuck perhaps? (Which I just found out originated from the Yiddish word for penis! TMYK)


Sent from my Smartphone

 Yes I was aware of the connotations, was not sure though if alhoop had a straight face or not when he asked the question  .

[paulie]

The AD587JQ and it's "better" brother the AD587UQ are the only monolithic 10V references that I have been able to find that are still sold in hermetic packages. 

So since none of the top brands use that part should we assume production of all lab grade instruments in the world has ceased? Is there any clear data available showing just what the impact is for using plastic dip? By clear I mean understandable to a human being.

[mrflibble]

The AD587JQ and it's "better" brother the AD587UQ are the only monolithic 10V references that I have been able to find that are still sold in hermetic packages. 

So since none of the top brands use that part should we assume production of all lab grade instruments in the world has ceased? Is there any clear data available showing just what the impact is for using plastic dip? By clear I mean understandable to a human being.

I was wondering the same thing. I don't follow that market all that closely, but to the casual observer it seems that there is not that much development going on. Combine that with some parts going EOL, and it seems the amount of options is reducing...

As for the plastic DIP, how viable is it to use the PTFE/FEP trick DigilentMinds mention on the entire dip package? As in do something clever with the leads if required, bake it, and heat shrink it. Is that viable, or even useful?

[paulie]

Yes there is an advantage to batteries.

I can verify that too from personal experience. Even with a crude 0.1mv meter any part of my system connected to mains gear made reading very difficult. Specially USB from a PC. When I went to 0.01mv resolution it obviously got much worse and mains connected gear was no longer an option at all.  Using 9v batteries for meter and voltage reference improved everything.

Another fellow who was using commercial precision PSU and lab grade meter when reading my same references experienced extreme noise. Just being near it threw readings off not to mention his issues with radio interference. My battery setup had about an order of magnitude less reading these same units compared to his graphs.

ps. In order to datalog to a PC I had to resort to using an opto-isolator. Even 4N35 type had too much noise coupling so used a homemade version consisting of IR diode and photo transistor (1" separation). Fortunately sending serial to a PC requires only one pin.

[codeboy2k]

RE: batteries...

I have, for a long time now, been considering building my own state-of-the art standard.  I have been watching these threads with great interest, in order to learn from those who know much more than I do. 

I currently have the Voltage Standard VREF10-003 and the Awesome14 version.  Both are stable enough for my current needs, but I will repeat, I cannot verify if it's any better than 100 ppm.  I only have two 5-1/2 digit meters here, so these standards were good enough for my current needs.

But I always thought, if I ever built my own really, really top-shelf volt-standard based on the knowledge shared in these threads, then I would definitely do it with batteries only (along with all the other best-practices the forum has been discussing in the many threads).  I thought about how to have a SLA battery running the reference, and charging the battery too, without getting any line noise into the reference circuit. I don't think it can be done, so I thought I'd need 2 batteries, one running the reference and the other one being charged, then switch over with a hard switch or relay (make before break, so the reference never loses power). I wanted to have the unit battery powered, but constantly plugged in being charged.  Maybe doing that will still introduce noise, due to the proximity of the AC charging circuit to the reference, even if it's not actually in the reference circuit at all. Maybe the AC magnetic fields will have some ppm effect.. I don't know this yet, but I hope I will build it up one days and find out.

[Terabyte2007]

RE: batteries...


I currently have the Voltage Standard VREF10-003 and the Awesome14 version.  Both are stable enough for my current needs, but I will repeat, I cannot verify if it's any better than 100 ppm.  I only have two 5-1/2 digit meters here, so these standards were good enough for my current needs.

The Awsome14 version is better than 100 ppm but I am not quite convinced it meets the advertised specification at this point.

[alhoop]

Sooo.. that means everyone else are also 'goobers' ??. 
What definition are you referring to ?.

I was the one who "attacked" him by calling him a goober. It means, "an unsophisticated person; a yokel," to quote OEAD. It's an old term used in the southern US.

Common usage is that of a lighthearted insult. Akin to schmuck perhaps? (Which I just found out originated from the Yiddish word for penis! TMYK)


Sent from my Smartphone

 Yes I was aware of the connotations, was not sure though if alhoop had a straight face or not when he asked the question  .

Obviously I didn't have a straight face and it did elicit a response from the true 'goober'  here.
The question was in earnest - I just bought a DMMCheck Plus from Voltagestandard.
Thanks for the helpful answers.

Al

[Terabyte2007]

The AD587JQ and it's "better" brother the AD587UQ are the only monolithic 10V references that I have been able to find that are still sold in hermetic packages. 

So since none of the top brands use that part should we assume production of all lab grade instruments in the world has ceased? Is there any clear data available showing just what the impact is for using plastic dip? By clear I mean understandable to a human being.

I was wondering the same thing. I don't follow that market all that closely, but to the casual observer it seems that there is not that much development going on. Combine that with some parts going EOL, and it seems the amount of options is reducing...

As for the plastic DIP, how viable is it to use the PTFE/FEP trick DigilentMinds mention on the entire dip package? As in do something clever with the leads if required, bake it, and heat shrink it. Is that viable, or even useful?

The humidity effect on epoxy [IC packages, board material] is well known.  The epoxy absorbs water vapor [humidity] from the air, and "swells".  The board dimensional changes affect some parts mounted on the board if they are sensitive to board stress.  This can be so high that it actually cracks surface mount resistors and capacitors in the larger packages if they are not designed to absorb this kind of abuse.  And so it is with reference IC's and precision [non-chopper] op-amps.  When the epoxy package absorbs the water, it changes dimensions and this puts a strain on the IC die, resulting in a shift in output.  This is mostly caused by on-chip resistors, that act like strain gauges.

My PTFE/FEP dual-wall heat-shrink trick should work well to stop the water vapor infusion 100%, but it will not stop another thing that happens to reference IC's and precision [non-chopper] op-amps in plastic packages, and that is mechanically caused hysteresis which will shift the output based on previous temperature history.

A method I have used which includes epoxy resins is degassing the epoxy mixture in a heated vacuum chamber before molding the circuit or package. Use a high-quality epoxy, degassing and dehumidifying the mixture in the process and while curing seems to render very good results. Epoxy are far more susceptible to moisture before they are hardened, but I believe that reducing the trapped air and moisture before and during curing seems to help quite a bit.

[timb]

Another option is to include a 40c PTC heater in the enclosure. I found a 15x15mm unit recently that runs on 5V@1W.

The advantages of a PTC heater are that it's self regulating. No messy PID loops or control circuits; give it power and it stays at a constant 40c.

If you were to use a small water tight enclosure, you'd be set I think. Maybe throw in a desiccant pack before sealing to take out any base humidity.


Sent from my Smartphone

[Terabyte2007]

Timb, can you post a link to that ptc heater you found?

[timb]

Sure thing, about to go into a meeting, when I get home in a couple of hours I'll grab it off my computer. =)


Sent from my Smartphone

[Terabyte2007]

Thanks man!

[timb]

Timb, can you post a link to that ptc heater you found?

Okay, I can't seem to find the auction with them available for Buy-It Now, but here's an auction version: http://www.ebay.com/itm/PTC-heating-element-40-1W-5V-consistant-temperature-ceramic-Thermostatic-/291388048996

That same seller might have them in his store, haven't checked yet.


Sent from my Tablet

[paulie]

Apparently not banned but more likely just hiding out. And all reviews of his product so far indicate performance somewhat better than advertised. However this has not deterred detractors.

There are similar products available from one other company such as this unit with specs not quite so good but slightly cheaper:

http://shop.voltagestandard.com/product.sc?productId=3&categoryId=1

Or this one with case and similar specs as the Eboy top unit but costs more ($300 vs $100):

http://shop.voltagestandard.com/product.sc?productId=2&categoryId=1

This does come with rubber feet which might be perceived as an advantage.

Both companies imply approximately 6 month drift stability. The biggest difference is a "pretty" PCB for the above vs Eboy's perfboard construction which annoys the hell out of most here and also they just don't like his attitude. Mainly a conflict with their religious views.

[Excavatoree]

The biggest difference is a "pretty" PCB for the above vs Eboy's perfboard construction which annoys the hell out of most here and also they just don't like his attitude. Mainly a conflict with their religious views.

Perfboard isn't the problem.  It isn't done in a "workmanlike manner."  I can understand not being able to design and get a PCB, but geez,  he can't tin wires and solder them to the perfbord without several strands all splayed out in different directions.  Solder blobs and flux blobs are all over the place, and it looks like he placed the components with a shotgun.   When questioned, he claimes that his construction is "superb" and there is a reason for doing as he did it.  Sorry, there is no reason to badly tin a wire with strands going in every direction with a solder blob.  That ads NOTHING to the design, buy says a lot about his attitude.

Bob Pease and Jim Williams had messy PROTOTYPES.  Bob used to "tack on" multiple components and "touch them in" to compare performance.  They weren't attractive, but there was a purpose.  As someone said, they weren't finished, sell-able products.   I know it's inexpensive, but honestly, 20 minutes spent fixing the layout, and some care spent while putting it together so it doesn't look like a dog's breakfast would do wonders.  It causes one to think:  "If he's that sloppy with the construction, was he equally sloppy with the design?"

[Terabyte2007]

The biggest difference is a "pretty" PCB for the above vs Eboy's perfboard construction which annoys the hell out of most here and also they just don't like his attitude. Mainly a conflict with their religious views.

Perfboard isn't the problem.  It isn't done in a "workmanlike manner."  I can understand not being able to design and get a PCB, but geez,  he can't tin wires and solder them to the perfbord without several strands all splayed out in different directions.  Solder blobs and flux blobs are all over the place, and it looks like he placed the components with a shotgun.   When questioned, he claimes that his construction is "superb" and there is a reason for doing as he did it.  Sorry, there is no reason to badly tin a wire with strands going in every direction with a solder blob.  That ads NOTHING to the design, buy says a lot about his attitude.

I would have to agree. I have and still do Perfboard layouts all the time and I take the time to make mine neat and tidy. If I do a Vcc/Vss bus then I use a bare copper wire tack it at the appropriate locations and make nice angles to support my components. If you get blobs of solder then you redo them! Hell, I have seen some beautiful wire-wrap in my earlier days that actually looked neat and tidy.

[paulie]

honestly, 20 minutes spent fixing the layout, and some care spent while putting it together so it doesn't look like a dog's breakfast would do wonders.

I agree. But if he does make thousands of dollars an hour like he said then those little 20 minute segments would add up. Time is money.

See... you guys aren't the only ones that can put words in his mouth.