Your simplified diagram is slightly wrong - the unit produces a negative reference, which is converted to positive via the inverting amplifier. I knew a UK company that made stuff like this- a big test rig held a couple of hundred zeners to age over several weeks & they then picked the best ones. They designed an amp module in the 1970s which was a chopper built from many 741's and discretes, used up til ~2000 when I redesigned it for them with a modern chopamp & reference IC.
Nice one! Love it when you explain the datasheets, good to follow, since my day job only allows me to swap modules and not component level. Sign of the times!
@ivaneduardo I think I can answer your question, at least in the case of a voltage source. You can get a very accurate voltage reference directly linked to QM using a Josephson Junction. This is superconductive though so you have to have low temps. But absolutely stable and very accurate. You calibrate that using a Watt balance to measure planks constant.....
@MichelDeSarcelles Yes, they would have individually tested and selected I'm sure. "Close to zero" ain't zero though, so it still matters. You can get special "zero tempco" foil resistors too, once again, close to zero, but not zero :-> The exact parts used in this instrument aren't known though.
Wow, I love this kind of teardown / explanation videos, I always learn about a couple of new topics at least. Same with the "obscure stuff" tutorials, like the burden voltage one tutorial.
Not normally for DIY but its nice to know that the test equipment you are using is accurate to some degree. It all depends on the accuracy that's required for the work or project you are working on ! Other wise you can't trust any piece of equipment to be accurate. Example, is you power supply really giving out 5V when it says so? Is your multi-meter telling you lies? Is your frequency generator really giving you 10MHz that it's set to? That's what calibration is all about !
I work in Boston. I'm an electrical engineer working in a biotechnology company. We design and manufacture cell sorters (cytometers). We definitely make stuff still!
They used a selected temp. compensated 6.2 V reference diode. See Walter Jung 's Analog Cookbook early '80s edition! Some of these diodes had multiple junctions in series , cancelling each other's temp. coefficients over a wide temperature range!These units were trimmed by comparing it to a primary (josephson) standard.
I bet that daughterboard setup was their way to replace an obsoleted chopper amp module that was part of the original design. The layout of those PCB contacts looks like the arrangement that Teledyne/Philbrick and others used on some of their potted hybrid opamps and other analog modules. When the original module went out of production, perhaps that board was made as a replacement, so they wouldn't need to respin the main PCB?
23C is old standard and 20 new one? I guess the guy somehow mixed that up. Practically every instrument specifications are defined for 23C because it's much closer to usual working temperatures. That is one of the reasons why we recently switched to 23C from 20 in all laboratories where it was possible in Czech Metrology Institute - length is of course problem so they stays at 20C.
The whole thing looks DIY, especially the PCB. I've never seen anything like this sold commercially (then again, I haven't seen a lot of gear from the inside). I'm not saying that that's a bad thing, just that it looks as if a hobbyist like myself had done it. Charming. :)
@ivaneduardo I think I can answer your question, at least in the case of a voltage source. You can get a very accurate voltage reference directly linked to QM using a Josephson Junction Reference. This is superconductive though so you have to have low temps. But absolutely stable and very accurate. You calibrate that using a Watt balance to measure planks constant..... but those get doen to the ppb range. exotic stuff
I like the teardowns, but as a novice electronics hobbyist, I would love to see more videos focusing on tutorials and design ideas. Having said that, this video went into more detail of the reasons and considerations put into the design of this source. Very nice explanation of the schematic! Thanks for all the stuff you do Dave, we love it.
Now that is brilliant, I just wanted to know a bit about voltage dividing with resistors, now I know every thing and also know how to make a really cool voltage souce. damn you dave :)
I think what they are doing is... adding various combinations of these six resistors to get every value. e.g. you can use two 3K, one 2K and Three 1K... to make anything from 1K to 10K.
@Gameboygenius For such a short run, with high input impedance, there is no benefit in 4 wire in this instance. The silence, I meant to cut out more of that, looks like my edit failed. Charles's phone rung with an important call :->
Great video dave! What an amazing instrument, it really is incredible how good this stuff is just being made from careful design and parts selection. Aside from the switches and resistors nothing amazing or incredible expensive. What did that odd 4-load component turn out to be? I thought I caught it on the schematic with a symbol like a TVS diode, but I'd be curious to know what its purpose is. Also I'd like to see a similar vid for the HP 3478 when you calibrate it with your new standard!
17:30 what is the name or brand-name of this transparent plastic insulator ? I've seen it before many many times but I never knew what they are called besides "plastic insulator"
Boston, yeah! That's the closest large city to me. Boston is a huge engineering city, but I don't think many companies do all out electronics products such as this.
@hoppes9 This started out as a "good buy review"/"teardown", but like I said in my comment, "... this video went into more detail of the reasons and considerations put into the design of this source. Very nice explanation of the schematic!" So, yes, this video turned into more of a tutorial than it started out as, but I would like to see more tutorials from Dave. Things starting with a project/circuit in mind, explaining it and different considerations associated with it.
@ivaneduardo747 i second that question, and now that i think of it, how do they calibrate the equipment used to calibrate calibration equipment? Where do they get the ABSOLUTE reference? i can imagine some scientists un a penta layered faraday cage, 50 meters under the ground in the south pole XD (just kidding, but a good question though, i too would like to know the answer, or even better, a video by dave :P)
You would think they might have chosen a better constant current source, like a Wilson with a stabilizer cap between the tied bases (BJT design) and -Vee or at least a current buffered source
this video demonstrates that to make a precise instrument, rather than complicated electronics, you need a knowledge of the fundamental physical principles of matter and thermodynamics. Then you will need few but quality components
Great video but I do not understand the function of the decades. On video (time stamp 12:00, 17:38 and following) I can see six resistors for each switch. How can this divide the voltage into ten steps?
I have thought that you could design a way to calibrate such an instrument and in fact many instruments using a GPS referenced frequency standard. For this example you use the voltage reference standard to drive a RCL circuit and the frequency out dependent upon the reference voltage in. Use a frequency counter tied to the GPS standard and you have a calculated accuracy of at least 10^-7.
The insulated spade terminals leading to the output binding posts don't look like they have been crimped by a pair of insulated-terminal crimpers. Were they crimped with uninsulated crimpers, soldered on or what?
By the way, how do you calibrate standard calibration equipment? It's not like calibrating weight scales, where you just use a copy of the kilogram prototype, as far as I can tell.
If someday you happen to find a soviet-russian made instrument, jump on the opportunity, you will have fun tinkering weirdish electronics and it will give one more great video !
Hi people. Just scored one of these units on ebay. I got a quick question about this voltage standard. When i zero out my multimeter connected to the supply, is there a difference in whether the voltage standard is set to ground as output, vs having all dials set to 0 and the output knob being on either + or - polarity, not ground.
Why didn't you go all the way out and use sense return in the cal lab? Also, why did you cut out the audio near the end? Dirty talk in this pornographic setting? ;)
Dave, i've found one of these units on ebay but i have no luck to purchase it(no enough funds:P)... but imho price is pumped to high. Check it on ebay "electronic development corporation" USD 850 is price.
Jardar Sunde Olsen amazing what a defunded nasa can do. to be fair most of these are privat enterprises now like space x you find these companys world wide now china russia uk germany france and so on infact if it was not for the russian rocket motors america would not have done much. look up operation paperclip since i assume you havent
Yeah, I know what operation paperclip was all about. You talk about Russian rocket motors and operation paperclip as if they were linked. Both the Americans and the Russians used German engineers in their development of rocket motors and in other fields. The Russians has operation Osoaviakhim. And the Americans landed people on the moon before they had access to any Russian rocket engines. Granted the Russian had more efficient engines, but to claim that America would not have done much without Russian rocket motors is just ignorant. And to assume that the Americans would not have been able to develop any technology of their own without German scientists is naive.
Your simplified diagram is slightly wrong - the unit produces a negative reference, which is converted to positive via the inverting amplifier.
I knew a UK company that made stuff like this- a big test rig held a couple of hundred zeners to age over several weeks & they then picked the best ones.
They designed an amp module in the 1970s which was a chopper built from many 741's and discretes, used up til ~2000 when I redesigned it for them with a modern chopamp & reference IC.
Thanks, I really appreciate that Dave. Cheers, Martin.
Thank you Dave, for teaching me the difference between accuracy and stability.
Oh hi max!
@@justin.campbell Hi :-)
Excellent video Dave. Lovely kit. Great seeing the cal lab. Cheers, Martin.
Nice one! Love it when you explain the datasheets, good to follow, since my day job only allows me to swap modules and not component level. Sign of the times!
@ivaneduardo I think I can answer your question, at least in the case of a voltage source. You can get a very accurate voltage reference directly linked to QM using a Josephson Junction. This is superconductive though so you have to have low temps. But absolutely stable and very accurate. You calibrate that using a Watt balance to measure planks constant.....
@MichelDeSarcelles Yes, they would have individually tested and selected I'm sure. "Close to zero" ain't zero though, so it still matters. You can get special "zero tempco" foil resistors too, once again, close to zero, but not zero :-> The exact parts used in this instrument aren't known though.
I like all your videos. I don't mind if you mix them up. Tutorials, teardowns, interviews, etc. Keep them coming!
Wow, I love this kind of teardown / explanation videos, I always learn about a couple of new topics at least. Same with the "obscure stuff" tutorials, like the burden voltage one tutorial.
I can't imagine where such a precision is needed in modern digital DIY projects
It's not.
Not normally for DIY but its nice to know that the test equipment you are using is accurate to some degree.
It all depends on the accuracy that's required for the work or project you are working on !
Other wise you can't trust any piece of equipment to be accurate. Example, is you power supply really giving out 5V when it says so?
Is your multi-meter telling you lies? Is your frequency generator really giving you 10MHz that it's set to? That's what calibration is all about !
I work in Boston. I'm an electrical engineer working in a biotechnology company. We design and manufacture cell sorters (cytometers).
We definitely make stuff still!
Am I the only one that noticed the Bob Pease reference in the description? I like how you put that in. RIP legend Bob Pease
They used a selected temp. compensated 6.2 V reference diode. See Walter Jung 's Analog Cookbook early '80s edition!
Some of these diodes had multiple junctions in series , cancelling each other's temp. coefficients over a wide temperature range!These units were trimmed by comparing it to a primary (josephson) standard.
I enjoyed this video very much, Dave. HOWEVER, we still have a MYSTERY 4-PIN DEVICE that needs some explaining . . . ;)
I bet that daughterboard setup was their way to replace an obsoleted chopper amp module that was part of the original design. The layout of those PCB contacts looks like the arrangement that Teledyne/Philbrick and others used on some of their potted hybrid opamps and other analog modules. When the original module went out of production, perhaps that board was made as a replacement, so they wouldn't need to respin the main PCB?
23C is old standard and 20 new one? I guess the guy somehow mixed that up. Practically every instrument specifications are defined for 23C because it's much closer to usual working temperatures. That is one of the reasons why we recently switched to 23C from 20 in all laboratories where it was possible in Czech Metrology Institute - length is of course problem so they stays at 20C.
Thanks. BTW, I've linked your channel on my web home page.
The whole thing looks DIY, especially the PCB. I've never seen anything like this sold commercially (then again, I haven't seen a lot of gear from the inside). I'm not saying that that's a bad thing, just that it looks as if a hobbyist like myself had done it. Charming. :)
criscros7
These were hand built after having been ordered! Never mass produced!Hence the diy appearance.
handy piece of gear. very surprised at the simple board design. great vid again mate.
@ivaneduardo I think I can answer your question, at least in the case of a voltage source. You can get a very accurate voltage reference directly linked to QM using a Josephson Junction Reference. This is superconductive though so you have to have low temps. But absolutely stable and very accurate. You calibrate that using a Watt balance to measure planks constant..... but those get doen to the ppb range. exotic stuff
I like the teardowns, but as a novice electronics hobbyist, I would love to see more videos focusing on tutorials and design ideas.
Having said that, this video went into more detail of the reasons and considerations put into the design of this source. Very nice explanation of the schematic!
Thanks for all the stuff you do Dave, we love it.
The virtue of the Kelvin-Varley divider is that it cancels out thermoelectric effects between the switch contacts
Thank you very much for very informative video. I have watch it 5 times. What a surprise!!! Big box, small board and no vodoo magic.
Now that is brilliant, I just wanted to know a bit about voltage dividing with resistors, now I know every thing and also know how to make a really cool voltage souce. damn you dave :)
@bfestevao Yeah, possible, but you'd have to weigh up how much improvement you'd get. The tempco is already more than low enough for my use at least.
I think what they are doing is... adding various combinations of these six resistors to get every value. e.g. you can use two 3K, one 2K and Three 1K... to make anything from 1K to 10K.
@Gameboygenius For such a short run, with high input impedance, there is no benefit in 4 wire in this instance.
The silence, I meant to cut out more of that, looks like my edit failed. Charles's phone rung with an important call :->
Great video dave! What an amazing instrument, it really is incredible how good this stuff is just being made from careful design and parts selection. Aside from the switches and resistors nothing amazing or incredible expensive.
What did that odd 4-load component turn out to be? I thought I caught it on the schematic with a symbol like a TVS diode, but I'd be curious to know what its purpose is.
Also I'd like to see a similar vid for the HP 3478 when you calibrate it with your new standard!
@CampKohler They look to be using uninsulated crimps then a sleeve slid over the end, but only Dave can confirm that.
17:30 what is the name or brand-name of this transparent plastic insulator ? I've seen it before many many times but I never knew what they are called besides "plastic insulator"
Boston, yeah! That's the closest large city to me. Boston is a huge engineering city, but I don't think many companies do all out electronics products such as this.
@hoppes9 This started out as a "good buy review"/"teardown", but like I said in my comment, "... this video went into more detail of the reasons and considerations put into the design of this source. Very nice explanation of the schematic!"
So, yes, this video turned into more of a tutorial than it started out as, but I would like to see more tutorials from Dave. Things starting with a project/circuit in mind, explaining it and different considerations associated with it.
The resistors in the 7-decade Kelvin-Varley chain alone cost 1.600 Euros on Mouser, in 50 ppm tol. and
1 euro 60 cents or 1600 euros?
@ivaneduardo747 i second that question, and now that i think of it, how do they calibrate the equipment used to calibrate calibration equipment? Where do they get the ABSOLUTE reference?
i can imagine some scientists un a penta layered faraday cage, 50 meters under the ground in the south pole XD (just kidding, but a good question though, i too would like to know the answer, or even better, a video by dave :P)
old is gold
That would be Cromwell Fleetwood Varley (C. F. Varley on Wikipedia) (1828-1883). Worked on the telegraph.
Dave please take us for the trip to this metrology lab. I'm sure that many peoples (including me) are very curious how does the lab work's.
49:15 you've pulled out the test lead :-)
You would think they might have chosen a better constant current source, like a Wilson with a stabilizer cap between the tied bases (BJT design) and -Vee or at least a current buffered source
i expected much more inside, but as we see, its enough
saw the "last calibration date 2008" and thought, wow that was ages ago, until i noticed this video is from 2011 xd
this video demonstrates that to make a precise instrument, rather than complicated electronics, you need a knowledge of the fundamental physical principles of matter and thermodynamics. Then you will need few but quality components
Nice video! Thanks, Dave!
Will you do video on your HP meter calibration?
Great video but I do not understand the function of the decades. On video (time stamp 12:00, 17:38 and following) I can see six resistors for each switch. How can this divide the voltage into ten steps?
I have thought that you could design a way to calibrate such an instrument and in fact many instruments using a GPS referenced frequency standard. For this example you use the voltage reference standard to drive a RCL circuit and the frequency out dependent upon the reference voltage in. Use a frequency counter tied to the GPS standard and you have a calculated accuracy of at least 10^-7.
NICE SCORE!
1lb of electronics in a 10lb box !! What were they thinking when they made the case that huge? Does bigger sell better in measurement instruments?
Woah, that thing looks homemade :D
i work in fasteners. those nuts are just brass. still conductive, pretty.
1991 those are new, but the rest look like its from the early -80 or such.
The insulated spade terminals leading to the output binding posts don't look like they have been crimped by a pair of insulated-terminal crimpers. Were they crimped with uninsulated crimpers, soldered on or what?
30 ppm stability out of a non ovenised reference; *greybeard noises intensify*
*Did he go to Ireland to get it calibrated? That guy doesn't sound australian.*
That is an awesome bit of gear you have there, Dave. How much did it cost you? :)
By the way, how do you calibrate standard calibration equipment? It's not like calibrating weight scales, where you just use a copy of the kilogram prototype, as far as I can tell.
@aptsys Now that you mention it, that is what it looks like, but I can't tell for sure. OK, Dave, satisfy my curiosity, please.
If someday you happen to find a soviet-russian made instrument, jump on the opportunity, you will have fun tinkering weirdish electronics and it will give one more great video !
nope I dont think they make anything in Boston anymore
The old video were great... Hows the solar system going
You keep saying "temperature compensated". I think you mean "temperature controlled". These are different things.
Dude....please do krohn hite 526...we are trapped in Testamatic
Hi people. Just scored one of these units on ebay. I got a quick question about this voltage standard. When i zero out my multimeter connected to the supply, is there a difference in whether the voltage standard is set to ground as output, vs having all dials set to 0 and the output knob being on either + or - polarity, not ground.
Why didn't you go all the way out and use sense return in the cal lab? Also, why did you cut out the audio near the end? Dirty talk in this pornographic setting? ;)
That is cool
How do they calibrate the calibrators?
With a set of calipers?
Dave, i've found one of these units on ebay but i have no luck to purchase it(no enough funds:P)... but imho price is pumped to high. Check it on ebay "electronic development corporation" USD 850 is price.
@slaithen You don't think this is a tutorial?
mmm nice
I can get a krohn-hite 5100a cheap is that a good unit.?
Can you sent me the circuit diagramm of the MV106J ?
That would be great :-)
can you do some more tutorials ?
10? Mine goes up to 11! XD
@bfestevao You could just air condition your lab.
Does exist any schematics or reference for that kind of DC reference in pdf for free?
its from the usa the land of hype.... if it was not for operation paperclip they could not wipe there own arses
+Gavin Irvine Yeah, or send people into space, or robots to Mars or other similar basic stuff...
Jardar Sunde Olsen amazing what a defunded nasa can do. to be fair most of these are privat enterprises now like space x you find these companys world wide now china russia uk germany france and so on infact if it was not for the russian rocket motors america would not have done much. look up operation paperclip since i assume you havent
Yeah, I know what operation paperclip was all about. You talk about Russian rocket motors and operation paperclip as if they were linked. Both the Americans and the Russians used German engineers in their development of rocket motors and in other fields. The Russians has operation Osoaviakhim. And the Americans landed people on the moon before they had access to any Russian rocket engines. Granted the Russian had more efficient engines, but to claim that America would not have done much without Russian rocket motors is just ignorant. And to assume that the Americans would not have been able to develop any technology of their own without German scientists is naive.