I stole
nikonoid's thread a little, but probably your guys can tolerate little bit of more spamming of fancy resistors, eh?
It was a while before I posted any new threads. So here it is,
fresh article about ESI SR104 10000 reference standard resistor.
Lid cal report attached to my box:
Little peak inside
I'm not brave enough to go any deeper.
What happened to 4-wire lord Kelvin connection here???
Half-hour of cleaning and removing irrelevant ugly stickers...
Don't forget to clean connectors. Who know what eBay hands held them before.
No business for banana jacks or other non-metrology crap here. Proper TeCu binding posts!
To justify going to my site, I've added realtime calculator for output true resistance, based on lid alpha/beta and Rdev information.
Might be easy for beginner ohm-nuts to join up sub-ppm choochoos. Click on pic to go for it:
There is also offline python app, that does same thing.
Here it is, can be also used for any resistor with known alpha/beta/calibrated value, not only SR104.
Result of comparison my voodoo
Fluke SL935 ovenized prototype and some SR104 from EEVBlog members for TCR. All TCR curves are
relative, not absolute resistance deviation. +23.0C calibrated value taken as a reference.
Jee, that ovenized prototype leaving no mercy to the SR104. Having both resistors pretty much is win-win for the lab now, use FSL935 as working standard and don't ever worry about tempco, and use SR104 as long-term calibration standard. No wonder some other top dogs in metrology have
ovenized resistance standards too.
EXCEL file with data and graph.
Calibration check results in table below. Keithley 2002-4 definately need some calibration love, other folks are happily lurking around ~2ppm absolute, which gives me decent confidence for homelab resistance accuracy.
.
More detailed funky plots
Setup with 3458As
Next step is to get my FSL935 back from this month soon-to-be-done second calibration (to establish 6 month stability) from Process Instruments (I hope they don't forget this time to keep unit plugged to mains to keep batteries charged when not in measurement!). I'll use FSL935 to transfer resistance calibration to this SR104.
What would be best way (for lowest uncertainty) to do so, given I don't have ESI 242D?
I do have F5700A, K6221, HP3245, LTZ-based 10V box with 50mA driving ability and K2182 as a toolkit.