Author Topic: Teardown: Standard Resistors  (Read 142078 times)

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Offline wolfy007

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Re: Teardown: Standard Resistors
« Reply #225 on: July 29, 2020, 04:18:02 pm »
Just had this Fluke 750A Reference Divider open on my bench for a look, so took a few quick pictures.
« Last Edit: August 05, 2020, 02:10:08 pm by wolfy007 »
 
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Offline doktor pyta

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Re: Teardown: Standard Resistors
« Reply #226 on: August 04, 2020, 08:47:10 pm »
I found a mechanically damaged standard so I tore it down and saw something interesting.

It was made in Poland in the seventies by the 'Inco' factory.
It is 0.1 ohm, 1W in air/ 3W in oil. tolerance 0.01% Manganin.



It is built as parallel connection of two coils wound in opposite directions.
I measured the inductance and obtained 200nH.





 
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Offline TimFox

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Re: Teardown: Standard Resistors
« Reply #227 on: August 04, 2020, 08:50:58 pm »
Can you tell what insulation was used?  I know that cotton and silk were common, years ago, but I don’t know what was preferable in oil.
 

Offline doktor pyta

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Re: Teardown: Standard Resistors
« Reply #228 on: August 04, 2020, 09:06:26 pm »
First of all the manganin tape is coated with laquer or enameled.
It is wound on an aluminum bobbin covered with some kind of insulating paint.
The twine is used only as a spacer and mechanical holder for the manganin tape.

Offline HighVoltage

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Re: Teardown: Standard Resistors
« Reply #229 on: August 05, 2020, 08:24:35 am »

It is wound on an aluminum bobbin covered with some kind of insulating paint.


Interesting resistor, I have never heard of that company.

Are you sure it is an aluminum bobbin?
May be it is an insulator made of Aluminum Oxide?

What is its reading, is it still stable?
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Offline doktor pyta

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Re: Teardown: Standard Resistors
« Reply #230 on: August 05, 2020, 02:02:10 pm »
Yes, double checked that. The bobbin is for sure made of Al, but the winding has some free space to move.
Value measured: 0,0999975 ohm  (setup uncertainty approx. +/-30ppm).
The insulator looks rather like enamel which is sometimes used on cooking pots :)

Offline HighVoltage

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Re: Teardown: Standard Resistors
« Reply #231 on: August 05, 2020, 02:07:43 pm »
That seems to be a very nice Manganin resistor, they usually have 10ppm/K temperature drift.
May be you can find a nice new housing for this resistor.

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Offline doktor pyta

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Re: Teardown: Standard Resistors
« Reply #232 on: September 30, 2020, 11:18:51 am »
New puppy in the lab.


R4030-M1 (Р4030-м1) made in USSR wirewound 1G ohm standard. Umax 2500V
Tol 0.01%, TC in my case: alpha: 8ppm/C; beta: 0 (quoting individual specs sheet).


It is made as series connection of two microwire hermetic resistors (bigger than shown on a picture) and a selected resistor or potentiometer.



« Last Edit: October 06, 2020, 07:52:51 pm by doktor pyta »
 
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Offline tszaboo

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Re: Teardown: Standard Resistors
« Reply #233 on: October 01, 2020, 01:59:06 pm »
Just had this Fluke 750A Reference Divider open on my bench for a look, so took a few quick pictures.
What's that block in the middle? PN184986
Is that a lot of TO-18 style package resistors in a block?
 

Offline Gyro

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Re: Teardown: Standard Resistors
« Reply #234 on: October 01, 2020, 04:50:41 pm »
Just had this Fluke 750A Reference Divider open on my bench for a look, so took a few quick pictures.
What's that block in the middle? PN184986
Is that a lot of TO-18 style package resistors in a block?

That's the container for the main divider resistors. It's oil filled (note the filler bolt at the end). The 'TO18 style' things are hermetic feedthoughs.
Best Regards, Chris
 
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Offline antintedo

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Re: Teardown: Standard Resistors
« Reply #235 on: October 20, 2020, 05:28:53 am »
A look inside hermetically sealed Tinsley 5685A. Photo from DOI:10.1109/CPEM.2008.4574696
100 ohm variant specified at 2ppm/year and 2ppm/K.

Bifilar winding on a fiberglass bobbin with fiberglass spacers. PTFE and bakelite top cover. Paper authors point out poor design of the terminals. Joints seem to be arc welded. Selection of two wire diameters and the way wires are bent before welding makes the process very forgiving, which could indicate they use a simple method like manually pulsed TIG.
 
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Offline antintedo

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Re: Teardown: Standard Resistors
« Reply #236 on: October 20, 2020, 05:55:53 am »
HRU standard from Alpha AE (now Vishay).
Specified at 0.1ppm/year (!) 0.05ppm/K. Offered for ~$10k.

Metal foil process, but without any substrate. Ceramic, hermetic, oil filled resistive element body. The element is free floating and only attached by one edge to the body.
Interesting construction details can be found in DOI 10.1109/TIM.2011.2108613, 10.1109/TIM.2018.2879997.
 
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Offline MiDi

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Re: Teardown: Standard Resistors
« Reply #237 on: October 20, 2020, 04:32:09 pm »
Still waiting for the 10k  8)

For convenience with links - access to IEEE needed, but abstracts are for free:

Novel 100-Ω Metal Foil Resistor - 2011

Development and Evaluation of High-Stability Metal-Foil Resistor With a Resistance of 1 kΩ - 2015

Characterization of 1 kΩ Metal-Foil Standard Resistors and Continuing Drift-Rate Evaluation of 1 Ω and 10 Ω Standard Resistors - 2018

Quote from: Abstract from Characterization
A set of standard resistors is a key component of resistance calibration. We have been developing a series of compact superstable standard resistors that meet calibration laboratory demands. In this paper, we describe manufacturing and evaluation of 1 kΩ standard resistors. All the resistors elements are made with the “stress free bulk metal foil” technology. We found that all standard resistors show extremely small average drift rates, e.g., smaller than 10 nΩ/(Ω year) and small temperature coefficients typically around 35 nΩ/(Ω °C) at 23 °C. Moreover, continuing the evaluation of drift behavior of 1 Ω and 10 Ω standard resistors is discussed.

8x1kΩ, 1715 days eval: 3.3nΩ/Ωyr avg (-0.8 ... 5.4 max), TC a23 35nΩ/ΩK avg (-77 ... 55 max), TC b 0.83nΩ/ΩK² avg (0.0 ... 1.5 max)
*1nΩ/Ω = 1ppb = 0.001ppm
« Last Edit: October 20, 2020, 05:22:23 pm by MiDi »
 

Offline branadic

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Re: Teardown: Standard Resistors
« Reply #238 on: November 08, 2020, 11:48:50 am »
With respsect to the PTB website

we meanwhile can expect a different resistor inside the wekomm resistor standards compared to the VHA518 that was seen in the early units:

https://www.eevblog.com/forum/metrology/teardown-standard-resistors/msg891676/#msg891676

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Offline binary01

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Re: Teardown: Standard Resistors
« Reply #239 on: January 24, 2021, 11:21:36 pm »
We are a surely a strange bunch to be so interested in pictures of resistors!  But to me they look like fine pieces of artwork and I can appreciate the craftsmanship...
I'll add a couple of mine to the collection: 
1) Guildline 9200 Resistor / DC Shunt
Looks to be circa 1994, based on NRC (Canada) calibration sticker.

2) J. L. William (Australia) 1k Standard Resistor
I believe J. L. William was well regarded for carefully hand-made standard resistors with low TC in a since-gone era of Australian manufacturing.  This one was originally used by NMI Australia.

I have some others but they have been covered already in this thread.
« Last Edit: January 24, 2021, 11:31:04 pm by binary01 »
 

Offline tszaboo

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Re: Teardown: Standard Resistors
« Reply #240 on: March 24, 2021, 04:17:45 pm »
ELC DR-08 decade box, 8 decade, 10MOhm to 0.1 Ohm
1% nominal accuracy


The gray beards soldered 3 SMD parts, otherwise done by the machine.
Banana for scale.
 

Offline trobbins

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Re: Teardown: Standard Resistors
« Reply #241 on: December 13, 2021, 06:12:34 am »
Ok not in the same league as the GR1433 in post #170, and a wee bit older, and the subject of some abuse, but can anyone identify the type of wire used in the Gambrell Bros 4x decade resistance box (photo below) ?  The wire can make a joint in solder, and has a form of insulation covering.  All coils are wound on the same size wooden bobbin, and are wound bifilar.  I'm guessing 1930's but not much info available on Gambrell except for them exhibiting their instrument range in the 1920's and 30's, and they are from England.  Nearly every bobbin measures within about 0.1% (only a crude measurement so far with a Keithley 197) so this was likely a base grade lab 1R to 9,999R box for its time.
« Last Edit: December 13, 2021, 06:14:30 am by trobbins »
 

Offline Edwin G. Pettis

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Re: Teardown: Standard Resistors
« Reply #242 on: December 13, 2021, 06:11:15 pm »
The wire is Manganin or a similar alloy, wood bobbins would be somewhat out of the ordinary as ceramic was the standard bobbin material even back in the 1920s.  Constantan was another alloy commonly used but it had a higher TCR than Manganin (1892) and generally fell out of use as a precision resistor alloy but is still used today.  Both alloys can be soldered.
 
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Offline serg-el

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Re: Teardown: Standard Resistors
« Reply #243 on: December 28, 2021, 09:32:10 am »
YEW Type 2792 10 kOhm 1977



« Last Edit: January 31, 2022, 04:17:56 pm by serg-el »
 
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Offline Henrik_V

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Re: Teardown: Standard Resistors
« Reply #244 on: March 05, 2022, 10:40:45 pm »
Since the ESI DB62 already showed up here, and I just got my hands on three of them.. hold on , one is different, looks custom..
called SP 3972

pics to follow
Greetings from Germany
Henrik

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Offline Henrik_V

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Re: Teardown: Standard Resistors
« Reply #245 on: March 05, 2022, 10:45:20 pm »
The 10 Megs are 005, but no point , the 1Megs are market with +/- .003% , so I assume the 10 Megs are +/- 0.005%  ;D
« Last Edit: March 05, 2022, 10:59:31 pm by Henrik_V »
Greetings from Germany
Henrik

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Offline ZhuraYuk

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Re: Teardown: Standard Resistors
« Reply #246 on: May 18, 2022, 01:55:52 pm »
New puppy in the lab.

R4030-M1 (Р4030-м1) made in USSR wirewound 1G ohm standard. Umax 2500V
Tol 0.01%, TC in my case: alpha: 8ppm/C; beta: 0 (quoting individual specs sheet).

It is made as series connection of two microwire hermetic resistors (bigger than shown on a picture) and a selected resistor or potentiometer.


Here is how they actually look inside of P4030, without M1 letter.
 
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Offline HighVoltage

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Re: Teardown: Standard Resistors
« Reply #247 on: May 18, 2022, 04:21:17 pm »
Thanks for sharing the inside.

So, there are 2x 500 MOhm resistors in series with a small calibration resistor.
Can you measure the resistance of the small resistor?


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Offline ZhuraYuk

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Re: Teardown: Standard Resistors
« Reply #248 on: May 19, 2022, 12:48:03 pm »
Thanks for sharing the inside.

So, there are 2x 500 MOhm resistors in series with a small calibration resistor.
Can you measure the resistance of the small resistor?

Small one is 603.187 KOhm, big ones are 500 MOhm with precision 0,1%. Resistors model is МВСГ (MVSG) but the label is made of paper, such resistor are custom ones and are selected by tempco and can be created with non standard value. USSR industry was creating МВСГ resistors with printed labels and those are standard values and tempco.
 
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Offline Nanitamuscen

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Re: Teardown: Standard Resistors
« Reply #249 on: May 03, 2023, 04:05:55 am »
Resistance coil R310 0.01 Ohm USSR.
The inside is filled with oil.
https://drive.google.com/drive/folders/1tfFxWcOP6kJ6ihT4HXamelHuIbY_r7rb?usp=sharing

 
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