Bottled! 10K Resistor

[zhtoor]

-

[BNElecEng]

What is your end goal with this?

[kj7e]

This one $26 resistor will far outperform the the 10 parts in parallel your proposing;

https://www.digikey.com/product-detail/en/vishay-foil-resistors-division-of-vishay-precision-group/Y145310K0000V9L/Y1453-10KA-ND/2609894

Edit: I just pulled one out and put it on my 34465A.  When trying to obtain precision, the least expensive option will never yield the best results.

[eurofox]

This one $26 resistor will far outperform the the 10 parts in parallel your proposing;

https://www.digikey.com/product-detail/en/vishay-foil-resistors-division-of-vishay-precision-group/Y145310K0000V9L/Y1453-10KA-ND/2609894

I got one like that, build it into an hermetic enclosure with 4 decent binding post and 2 packet of silica gel.

This way I build a quite cheap 10K reference.

eurofox

[pigrew]

I like the idea of soaking the resistor in oil to help it maintain a constant temperature. You could add an RTD (Pt100?) in the bottle to get a better idea of the resistor's temperature. It'll certainly help with humidity, but my gut instinct is that it wouldn't help (much) with aging. You may be able to fix the TC by selecting components with complementary TC in some range.

[rhb]

The composite aging should be readily determinable by measuring the resistance and temperature during initial operation.  The aging curve is  almost certainly an exponential decline to a constant value.   This is based on basic mechanics of materials considerations, stress, strain and visco-plastic deformation.   That curve can be solved to ~1% for a period in the future equal to the length of time for which you have prior data.  If the part  changes by 40 ppm in a year,  with 6 months data one should be able to predict the change to under 1ppm over the course of the next 6 months.

The TC presents some interesting problems.  It would be nice to have histograms of the coefficients for a third order polynomial fit to a bunch of resistors and run some Monte Carlo simulations of the composite TC for various topologies.

[GigaJoe]

yeah, had play this way, relatively cheap resistors in par, seq but metal film only  .....

it doesn't has to be 100k  to make 10k, it can be 4.99 or 5.11. or better some variations where you can find it cheap
the most important are tempco, so ....

get as much as you can, resistors diff value ...
measure each one for tempco, it may be positive or negative even in one batch
calculate connection in sequence parallel , to compensate tempco and get in summary a close to target value but should be below it....
burn it at 150-170 C for a few days; that would be oxidation ageing process
construct it together
then adjust a final resistance value by altering a metal surface, increasing a resistance use a scalpel or something sharp , you may consider a high nominal in parallel,  if screw it up trow it and start again. then coating a few layers of conformal ....

then you can dump a final product in the bottle

that would be a week of fun and stable, low tempco product , with some patient and good source you may outperform $26 resistor

btw, 25ppm usually possible to find for .05-.1 ; 0.50 - kinda expensive to play with .. bought 5ppm for $.11

[RandallMcRee]

Lets just state the obvious: for over $100 time investment you may, perhaps, do better than buying a $26 resistor....

[eurofox]

yeah, had play this way, relatively cheap resistors in par, seq but metal film only  .....

it doesn't has to be 100k  to make 10k, it can be 4.99 or 5.11. or better some variations where you can find it cheap
the most important are tempco, so ....

get as much as you can, resistors diff value ...
measure each one for tempco, it may be positive or negative even in one batch
calculate connection in sequence parallel , to compensate tempco and get in summary a close to target value but should be below it....
burn it at 150-170 C for a few days; that would be oxidation ageing process
construct it together
then adjust a final resistance value by altering a metal surface, increasing a resistance use a scalpel or something sharp , you may consider a high nominal in parallel,  if screw it up trow it and start again. then coating a few layers of conformal ....

then you can dump a final product in the bottle

that would be a week of fun and stable, low tempco product , with some patient and good source you may outperform $26 resistor

btw, 25ppm usually possible to find for .05-.1 ; 0.50 - kinda expensive to play with .. bought 5ppm for $.11

outperform $26 resistor 

Resistance   10 kOhms   
Tolerance   ±0.005%   
Power (Watts)   0.6W   
Composition   Metal Foil   
Features   Moisture Resistant, Non-Inductive   
Temperature Coefficient   ±0.2ppm/°C   
Operating Temperature   -55°C ~ 125°C

And you need an instrument able to measure the resistance up to 0.005%

 

[GigaJoe]

eurofox, As  I said, it matter of source material and time spend, for tempco and value - how precisely you compensate and measure. and environment stable temperature and humidity, and equipment.   for example: HP3478A (5.5) pretty amazing in accuracy, for a last year 2 my units drift to 1 and 2 LSB. means it possible to measure .005%, consider to match with some reference ,  or use a bridge, if again, you have reference ....

[eurofox]

eurofox, As  I said, it matter of source material and time spend, for tempco and value - how precisely you compensate and measure. and environment stable temperature and humidity, and equipment.   for example: HP3478A (5.5) pretty amazing in accuracy, for a last year 2 my units drift to 1 and 2 LSB. means it possible to measure .005%, consider to match with some reference ,  or use a bridge, if again, you have reference ....

I never said that it is not possible but imagine checking a bunch of resistor the PPM + and PPM - and put them together the way they compensate each other and finally you need a "meter" that is calibrated and that is very precise. You stil need to solve the humidity influence.

I prefer to pay 27$, put it in an hermetical enclosure and know that I have a good reference.

eurofox

[kj7e]

hello friends,

something for your viewing pleasure.

best regards.

-zia

Your original idea was to just simply take 10, 100K parts and wire then in parallel then encase it in rosin, not to combing neg and pos TC parts to cancel out TC.

While you may be able to cancel out some or even most of the TC within a given window, you still end up a host of other issues.  Load life, self heating, aging rate which all lead to a drifty standard.  Now instead of one, you have many parts to account for and none will act or age exactly the same as the rest.

It would take a nice TEC box, at least one high end DMM (you will need more resolution and stability than a 3468 or 3478), and weeks of TC testing and component selection to save just a few bucks.  Not a very good trade off if your intent is to make a usable and stable reference vs academic.

[tszaboo]

yeah, had play this way, relatively cheap resistors in par, seq but metal film only  .....

it doesn't has to be 100k  to make 10k, it can be 4.99 or 5.11. or better some variations where you can find it cheap
the most important are tempco, so ....

get as much as you can, resistors diff value ...
measure each one for tempco, it may be positive or negative even in one batch
calculate connection in sequence parallel , to compensate tempco and get in summary a close to target value but should be below it....
burn it at 150-170 C for a few days; that would be oxidation ageing process
construct it together
then adjust a final resistance value by altering a metal surface, increasing a resistance use a scalpel or something sharp , you may consider a high nominal in parallel,  if screw it up trow it and start again. then coating a few layers of conformal ....

then you can dump a final product in the bottle

that would be a week of fun and stable, low tempco product , with some patient and good source you may outperform $26 resistor

btw, 25ppm usually possible to find for .05-.1 ; 0.50 - kinda expensive to play with .. bought 5ppm for $.11

outperform $26 resistor 

Resistance   10 kOhms   
Tolerance   ±0.005%   
Power (Watts)   0.6W   
Composition   Metal Foil   
Features   Moisture Resistant, Non-Inductive   
Temperature Coefficient   ±0.2ppm/°C   
Operating Temperature   -55°C ~ 125°C

And you need an instrument able to measure the resistance up to 0.005%

 

You aren't reading the datasheet right. For 10K, the tempco is "±0.2 ±0.6", AKA 0.8PPM/K. Welcome to the world of "bulshitting on the front page" by Vishay Precision group. Oh dont get me wrong this is still probably one of the best resistor money can buy.

[kj7e]

I wish I didn't see they had these in stock  ;
https://www.digikey.com/product-detail/en/vishay-foil-resistors-division-of-vishay-precision-group/Y407810K0000V9L/804-1059-ND/4233065

Oh well, also picked up a Hammond 1594RABK copper lined RFI/EMI shielded heavy duty plastic case that will be perfect for this.
https://www.hammfg.com/electronics/small-case/plastic/1594r

I already have some Pomona 3770 posts.  It will give me something to play with over the weekend while I'm grounded.

[rhb]

I wish I didn't see they had these in stock  ;
https://www.digikey.com/product-detail/en/vishay-foil-resistors-division-of-vishay-precision-group/Y407810K0000V9L/804-1059-ND/4233065

Oh well, also picked up a Hammond 1594RABK copper lined RFI/EMI shielded heavy duty plastic case that will be perfect for this.
https://www.hammfg.com/electronics/small-case/plastic/1594r

I already have some Pomona 3770 posts.  It will give me something to play with over the weekend while I'm grounded.

Did you go for the 50 or the 100 unit price break?

[CalMachine]

Perhaps this is a good place for a sneak peek 

[GigaJoe]

http://www.buy-components.com/components/vishay-foil-resistors/Y0078100R000V0L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y00781K00000V9L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y007810K0000V0L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y0078100K000V0L.html

fedex shipping around $40 (i think), make sense for a few nominal or group buy

[kj7e]

http://www.buy-components.com/components/vishay-foil-resistors/Y0078100R000V0L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y00781K00000V9L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y007810K0000V0L.html
http://www.buy-components.com/components/vishay-foil-resistors/Y0078100K000V0L.html

fedex shipping around $40 (i think), make sense for a few nominal or group buy

You know that's a scam site right?

[Vgkid]

*snip*
fedex shipping around $40 (i think), make sense for a few nominal or group buy

You know that's a scam site right?

Prices looked a bit too low

[kj7e]

Perhaps this is a good place for a sneak peek 

[CalMachine]

Secret magic sauce 

CalMachine: here is *the* BOX ! (with an SR104 in the bottom)
kj7e: what's in the box?
zhtoor: a bottle?

 

btw.
@CalMachine, a very nice looking ref. i can't really see, but is it 10K? *AND* those binding posts are $26 each.

best regards to all of you and keep em coming ....

-zia

Yes it is the 2nd 10k prototype!  Preliminary measurement logging is showing roughly -0.1 ppm/ºC TCR.

[GigaJoe]

You know that's a scam site right?

Frankly , had no idea ...
But, google the thing found at least 4 websites with the same design , same resistors, same price as above  .... *&^$*&$ ...
HK inventory has 0 (NULL) such items, seems whatever you find it , it a scam,  or a pure luck of old stock, if it so ...

[kj7e]

Once I saw the price, I did some searching and found many references to fraud.  You cant even buy VHP's used off eBay from China for those prices.

[CalMachine]

@CalMachine

don't you think that a pt100/thermister kelvin-sensed
(thermally bonded with main resistive element),
also in the box could be useful?
-0.1 ppm/degC tempco, could it be "compensated" with a copper wire?
(or a differential length on "secret magic sauce  ")

best regards.

-zia

The current prototypes employ a 2 wire connection on the side of the box to a 10 kOhm NTC thermistor.

[HighVoltage]

Perhaps this is a good place for a sneak peek 

What brand is blue banana plug for the guard cable ?
Or is this an original Fluke low emf cable?