Standard Oil Resistors

[flew-da-coup]

I was attending a symposium on Monday at the NCSLI on Resistance Standards. I was getting sleepy and wanted to leave. Then a guy from NIST started to speak. What came out of this man's mouth was something so profound that I woke up and listened to every word. I will get his paper and post it as soon as I can. This is the jest of it:

He had taken several standard Edison Type Resistors ( the kind most of us have in our baths ) and charted them over a long period of time @ 25 DegC. He heated them up to 30 DegC. and began to chart them. Of course we all know that temperature has a direct effect of resistance so the resistance changed. Not suprising, however when he then lowered the resistors back down to 25DegC and began charting them again there was a permanent change in resistance. He then did the opposite and charted them at 18 or 20 degC. The same thing happened.  He then changed the atmospheric pressure from sea level to a much high elevation and the standard resistors shifted again. Keep in mind that he charted these resistors for months. They were permanent changes in resistance!! Everyone there was amazed at what he discovered.  The shifts effect mainly primary labs such as the ones some of us work at. However, as we all know the secondary and field labs are tracable to us. The good news is that he did find one brand of resistors that had little or no effect from his expirement. The new Measurements International Limited ( MIL ) resistors showed little or no change in resistance. I will review the paper and try to clearify exactly what the impact will be. It may not be significant enough for most labs. Basically what I read into it ( and everyone else that was there ) was that when you ship your Standard Oil Resistors to NIST or another primary lab the resistance will change. Hours in the belly of an UPS airplane @ 30,000 to 40,000 feet and the extreme temperature changes from the changes in elevation will permanently change the resistor. I will let you guys know more after I read the paper. I hope that we all were mistaken in what we heard.

He did have something very cool. He found a Standard Resistor in the bowels of NIST that was made in 1899. and was last charted in 1949. He tested it and the change was only like 2ppm. Amazing. 

[MIRCS]

That's cool as hell.

Well get busy and decipher that paper. We want answers.....and sooner not later.

So in other words post whenever you have the chance

[flew-da-coup]

I am supposed to have all papers on the CD that they gave me. I will look at it tonight. I can e-mail anyone a copy as well.

[clacoste]

Wow, I used to ship those things half-way around the world....I would have never thought those physical changes were unrecoverable.  Thanks for the letting us know....

[Snap]

I am supposed to have all papers on the CD that they gave me. I will look at it tonight. I can e-mail anyone a copy as well.

I would like a copy of that if you don't mind.

[flew-da-coup]

Okay guys, I was trying to read the paper last night. It was hard too because my kids had their friends over for three hours. However, I am planning on reading the paper again tonight. It seems that some of the resistors tested came back after weeks and even months of stablization. A few never came back. They were L&M oil resistors. I think the most of us use L&M. I was correct about the MIL resistors when I said that they had no problems with stabilizing after the test. The MIL resistors are fairly new so I doubt most of us have them. The paper has charts that show you the actual changes. Everyone that wants a copy of the paper PM me with your e-mail address. Even though some did stablize after a considerable amount of time how are we to know when it is stabilized when they are our standards? You guys read the paper and post what you think about the impact this won't or will make. Even though some of the changes are small this will cause us to increase the uncertainty of our measurements. Like I said, PM me your e-mail address and I will send the paper to you. I will try to do this tonight if I don't forget.

[jwilley127]

Here's more info on the MI model 9210A that was discussed in the NIST presentation:

http://www.mintl.com/documents/9210a.dsrev.2_001.pdf

[PMEL_DEVIL-DOG]

wow....

[skolito]

coup,

Do you still have that paper? I am questioning my stds lab TUR at this moment and I need ammo

[flew-da-coup]

IF I cannot find it You can find it on the NCSLI website. It was a symposium at the Nashville,TN conference. I am still looking for it though.