Precision resistors CCCP

[Jester]

I picked up this set of Soviet resistors locally on Kijiji yesterday.

I'm not sure what to make of the notes on the image on the far right?

Wild idea of what these are worth?

[SeanB]

Notes are saying verified July 1992, due for inspection July 1993, with the lab code and checker's number on top, and his signature at the bottom, plus the official calibration lab stamp on the very yellowed paper label.

[bobAk]

Last resistor - reference (standard) resistor.  The remaining inscriptions when it was verified and when the next time to verify.

[HighVoltage]

I picked up this set of Soviet resistors locally on Kijiji yesterday.

What instrument did they use in the early 90th to get 10 digit resolution for a 1k resistor?

[bobAk]

Resistance comparator.

[bsdphk]

My math says 7.7 PPM/K tempco, that's kind of a lot, isn't it ?

[free_electron]

These are not resistors. They are indian chants...  unit of Oms ...

[Jester]

I picked up this set of Soviet resistors locally on Kijiji yesterday.

What instrument did they use in the early 90th to get 10 digit resolution for a 1k resistor?

I’m not sure but I also picked up a nice Agilent 34401A at the same time and the seller stated that the calibration of the meter was verified with a top of the line Advantest and that the meter was only out a few PPM, so well within spec. The yellow label looks like it was done recently.

[Jester]

My math says 7.7 PPM/K tempco, that's kind of a lot, isn't it ?

Seller stated that they use to (1990’s) submerge them in an oil bath to guarantee temperature swings were very slow.

These ones look better at 1-2 PPM per degree , but not cheap at $800 a pop.

https://www.instrumart.com/products/42862/wika-cer6000-reference-resistors

[guenthert]

I picked up this set of Soviet resistors locally on Kijiji yesterday.

What instrument did they use in the early 90th to get 10 digit resolution for a 1k resistor?

    I'd guess a bridge with a long scale (6 or more digits) DMM as null indicator and someone mindlessly copied all the digits there were.  Good luck setting the temperature of the oil bath with an uncertainty better than uK 

[bobAk]

Not necessarily an oil thermostat, you can also use an air one.  These resistors are supposed to be used at 20 degrees Celsius.  Their task is not low TC, but long-term stability.

Add. Not a bridge, but a comparator.  Although there were also long scale bridges.

[manganin]

The same question answered a year ago:

Those Krasnodar type standard resistors can be very good, but the quality varies a lot. You may need to buy ten to get one decent. And in real life the seal is far from hermetic, so nowadays it is hard to find anything not ruined by bad storage.

The primary resistor set of the Estonian national laboratory used to be Krasnodar, but that was at least ten years ago and they may have upgraded. Of course the examples found in high level labs are carefully selected.