My TRIAX cable shielded box project for Keithley Instruments

[TiN]

My eyes all broken trying to count zeroes on current scale Just use engineering notation, readers will say thank you..
Or you could recalculate resistance already for the graph.

DUT powered by Keithley 2450 SMU

[TiN]

All good deeds are punishable, I suppose. 
Suggesting better representation got me to ignore list, that's new 
Especially funny how shodan@micron didn't mind to reuse my graph code script though.

[coppercone2]

All good deeds are punishable, I suppose. 
Suggesting better representation got me to ignore list, that's new 
Especially funny how shodan@micron didn't mind to reuse my graph code script though.

picking a fight over nothing after code was modified is suspect, not to mention pointing out incompetence, as if it was not initially useful

i think someone here has some financial aspirations, sounds like co worker

[HighVoltage]

Nice setup, shodan@micron.

You might want to use pure copper crocodile clips

[bsw_m]

Project 1

OK, I am looking for improvements and hints of what to change or do differently for the next project.

Thanks for any suggestions.

Please consider the following.
Any insulating material can generates and stores a charge. Stacking PTFE sheets in an ultra-low current meter box can have many undesirable effects.
In my humble opinion, the measuring box for ultra-low currents should be all-metal without additional insulating materials.

[HighVoltage]

Ampporn!

After 6 months awaiting, 500GOhm Ohmite RX-1M arrived! Many thanks to PMElectronics(Mouser).
Ready to build a new "travel triax ampnuts reference box" for Russian&exUSSR amp-cal club.

Nice resistor!
What is the part number?

[HighVoltage]

Oh, that resistor RX-1M5009KE has 10% tolerance, I was hoping for better.
Looking forward to your measurements, I will order one as well.


 

[Melaa]

Do you have a microscope? Maybe there are cracks in the glass?
What was the humidity when you measured resistor?

I think its manufacturing defect.

[HighVoltage]

The stated TC of the datasheet is 50 ppm/°C

Yours is 12 fold higher, this must be a manufacturing defect.
Ohmite usually is very reliable in their datasheets.

I would claim a bad resistor and return it under warranty!

[Bill_at_PEARL]

Wonderinf where to find a 2-lug triax input cable to fit a Keithle

[Bill_at_PEARL]

That was supposed to read:
"I'm wondering where to find a 2-lug triax input cable to fit a '70s vintage Keithley Model 153 Microvoltmeter/Ammeter. See the pic.
TIA Bill"

[HighVoltage]

You need to look on ebay or similar places for used cables.
These cables are not easy to find.

Or you can use a 2 lug to 3 lug converter and then use the 3 lug cables.

 

[MiDi]

You could replace the 2 lug with a modern 3 lug as I did for a K617 EM.
Cheap alternative is to file one lug.

[HighVoltage]

There was just one 2-Lug Triax cable sold on eBay Germany.
Someone got lucky for Euro 70.

2600-ALG-2Konfektioniertes Prüfkabel, Triaxialkabel
https://www.ebay.de/itm/154545540559

[RaymondMack]

@HighVoltage

That's a three-lug cable. I have two just like it.

@Bill_at_PEARL

It's easy to spot a two-lug cable by looking for a Specialty Connector Co. branded triax connector, smaller alligator clips and seeing stripped triax all the way to the red lead (with the outer jacket and braid removed). This way the HI lead is guarded up to the alligator clip. Though newer two-lug cables use either a separate piece of coax or triax, rather than a straight through connection to the HI lead. I think the older construction is better for leakage.

I have two, two-lug to three-lug Keithley triaxial cables I made by trading connectors between a pair of two- and three-lug cables that I've been considering selling. They've been pretty useful to have, but since I bought a male two-lug to female three-lug adapter they are a bit extraneous now. After selling my 220 current source, the only other equipment with two-lug connections is my 617 electrometer and I primarily use it with an HP semiconductor test fixture rather than flying leads.

I would really recommend getting a decent HP/Agilent or Keithley test fixture. Flying leads are okay if you need to test in circuit or more general work, but for component characterization they aren't very easy to work with.

[ezeisel]

There is a Keithley 6011-10 cable for sale on ebay

https://www.ebay.com/itm/Keithley-6011-10-Cable-10ft-Triax-with-Test-Clips-NEW-/264891819342

I believe, but am not certain, that this one has a two-slot/lug triax bnc connector, so obviously verify that first if you consider buying one

[RaymondMack]

Wow 200 USD! Talk about overpriced. I paid around 80 USD each for my two-lug triaxial cables. If you can wait, good deals always come up. I remember seeing a whole bunch of Keithley two- and three-lug triax selling for 20 to 50 USD a few months back. They were pretty short cables though, maybe 2 to 5 feet long.

Anyways, the 6011-x are two-lug cables. It's the same part shown in the 5th photo attached to my previous post. These are the newer designs, but the older cables work fine too.

[HighVoltage]

@RaymondMack
You are correct, that 2600-ALG-2 is in fact a three lug cable
And the 6011-x are two-lug cables
I also have a few of each.

It is getting more difficult to find correct and good quality TRIAX cables on ebay.
The eevblog forum is probably partially at fault for this and the prices are rising.

The 2600-ALG-2 is still available from Keithley
And in Germany it is listed for Euro 382 plus VAT
https://www.calplus.de/keithley-2600-alg-2.html

[justanothername]

It's a little off-topic now but:

Pomona 4725 - 2 lug triax to 3 alligator

Pomona 5342 - 3 lug triax to 3 alligator

reasonably priced and on stock everywhere.