Does Vishay calibrate their precision resistors before selling them?

[nour]

I want to buy some precision foil resistors from Vishay and I was wondering, do they calibrate resistors individually before sending them to customers if not, Can I ask them to do so?

[TiN]

You can ask them to do it, but you are unlikely ready to pay for it (hundreds $$$USD .
Or try your luck with FSR which can come with calibration to 10ppm.

[nour]

So basically they don't do it  , I thought if I pay 500$ for some resistors, I wouldn't need to Calibrate them later 

[Cerebus]

I forget what Vishay call the service, but they have agents in a number of countries that will trim Vishay foil resistors to order. You can order arbitrary values and arbitrary precision. I don't know if they offer explicit traceability on these, but you can be pretty sure that if you order a 1k234 at 0.05% you'll get what you asked for.

I looked it up, they call them precision centres, see: www.resistors4u.com

[nour]

I have two main groups, one for some precision resistors that I will use as my lab standard (basically 1K,10K)--> this one I need it to be calibrated up to 6 digits or if possible more. The other group will contain also some matched precision voltage dividers and other individuals that I want to use to build a voltage ref.

[e61_phil]

I orderd my 3 VHP101 resistors with an "certificate of accuracy" from vishay. The certificate contains the values of the three resistors. Unfortunatley, without any information about the uncertainty.

[e61_phil]

Wouldn't they be guaranteed to be within spec? (whatever they were sold as, i.e 1%, 0.5% 0.05% or whatever..)  Isn't that the whole point of buying higher precision?

I ordered 10ppm tolerance. After a few days, they told me that they can't sell 10ppm tolerance (which was possible as I ordered some VHP101 at work). At this point I already paid the resistors. Therefore, the compromise was to sell 50ppm tolerance and include this certificate.