DMM Volts/Ohm Calibration Club - anyone interested?

[0.01C]

Hi @0.01C
Where did you buy the pure copper spade lugs?
enut11

I bought from taobao.com , ¥16 100pcs
If you want ,I can send you some .

[enut11]

Hi @0.01C
I went to taobao.com but could not see how to change the web-page to English. Can you sell me some copper lugs or buy some on my behalf? PM me if interested.
enut11

[0.01C]

Hi @0.01C
I went to taobao.com but could not see how to change the web-page to English. Can you sell me some copper lugs or buy some on my behalf? PM me if interested.
enut11

Sure ,I can send you some for free ,pm me

[TiN]

I'd like few too. Checking with some factory to make copper banana jacks too, still in progress to get quotation.

[0.01C]

I'd like few too. Checking with some factory to make copper banana jacks too, still in progress to get quotation.

no problem , pm me,
I think banana jacks is not good for low thermal .
taobao diy binding post @$3.5

[Vgkid]

taobao diy binding post @$3.5

Can you give us some links, please.
Thanks.

[TiN]

I agree, banana is a PITA to use for high precision stuff, but I'm not ready yet to modify my Keithley 2002's for binding posts

[SvanGool]

I would also be very interested in copper lugs, binding posts and banana plugs. FYI I now submit tinned copper items to DIY electrolysis and that works, for certain brands (some use another plating process) but it is a tedious process.

[Ash]

no problem , pm me,
I think banana jacks is not good for low thermal .
taobao diy binding post @$3.5

Those look good. I'd be keen to purchase some of those and the copper lugs as well. I've several projects coming up that I'd use the copper binding posts on and they look perfect.

If you could provide links that would be cool! Or if you wanted to run a group buy I'd be happy to be involved.

Thanks heaps.
Ash.

[VK5RC]

I agree, banana is a PITA to use for high precision stuff, but I'm not ready yet to modify my Keithley 2002's for binding posts

I have a similar opinion re a 34461.
A while ago I made a pair of lug to banana adapters (bodge city! - soldered)  and did a run with an ltz1000, with either the adapters in or out of the circuit, (main lead was Pomona low emf banana pair lead)
No difference detected with about 500 measurements in each run but constant temperature .
PS Aus Cal guys - the adapters are coming around with the ltz1000.
Robert
Edit   corrected model number

[0.01C]

no problem , pm me,
I think banana jacks is not good for low thermal .
taobao diy binding post @$3.5

Those look good. I'd be keen to purchase some of those and the copper lugs as well. I've several projects coming up that I'd use the copper binding posts on and they look perfect.

If you could provide links that would be cool! Or if you wanted to run a group buy I'd be happy to be involved.

Thanks heaps.
Ash.

here  https://world.taobao.com/item/40823926055.htm?fromSite=main&_u=g1paopr9dbf

[Ash]

here  https://world.taobao.com/item/40823926055.htm?fromSite=main&_u=g1paopr9dbf

Ok, first time I've used Taobao and had to rely on Google Translate. 

Hoping it works out! 

Thanks for the link!

Ash.

[0.01C]

here  https://world.taobao.com/item/40823926055.htm?fromSite=main&_u=g1paopr9dbf

Ok, first time I've used Taobao and had to rely on Google Translate. 

Hoping it works out! 

Thanks for the link!

Ash.

I just contact the binding posts seller , his email is qinchang001@sohu.com   ,if you have question ,you can contact him.

ps : I don't know the seller and bought from him only once.

[SvanGool]

I looked at Tao Bao to purchase 10 pieces but I am getting 240 Yuan shipping cost to Europe, which is about 32 Euro.

[0.01C]

I looked at Tao Bao to purchase 10 pieces but I am getting 240 Yuan shipping cost to Europe, which is about 32 Euro.

10pcs is about 100g ,ship from HK POST to Italy is about HKD40.

[SvanGool]

That would be indeed much better shipping cost (app. 4.57 Euro), now we need to convince the seller/Taobao 
Taobao recommends to contact the seller about the shipping cost, I did, no reply yet.

(Meanwhile we are polluting this thread from message msg1234742 on, maybe a moderator can move this to a new "Low thermal-EMF materials" thread)

[VK5RC]

With thanks to TiN and I believe SvanGool for putting design up on OshPark, and Lou et al for the Aus Cal Club 

A set of 6+ LTZ references being slowly built- aim is long term  - kept ON  - in a controlled temp cabinet, measured every 3 months or so - watch their drift (and that of my 3458 and 34461).
Difficult part will be getting lab at a constant temp without too much interference from heating-cooling system- I don't have a cellar - but tempted to dig a big pit!
I will probably heat / cool lab for 48hrs prior to measure time - then switch off.  I have also seen a little interference from the computer +/- PSU  / GPIB interface. Lots of known (and avoidable) interference from LED lights and other SWPSUs.
Most (5)  will be with TE UPS50 resistors, closest I can easily get to 13k is 13.3k (paralleled 20k and 40k), 70k (20k+50k), I have one set of Mr Pettis' left.
Four will be with LT1006 and 100nF across 1k and 120R, but two LT2057s
Four  will be with LTZ1000As but a generous Aussie gave an LTZ1000C and I have one 'C' of my own.
It won't be a quick result project!
Robert
VK5RC

[bitseeker]

A cellar would be a nice thing to have for relatively constant temp. The humidity might not be ideal, depending on where you're located. Underground/cave lab in the middle of the desert.

[GFWD1D]

Hi I'm new to this forum and would like to know more about your building of V refs.

I'm also interested in the calibration forum that has been set up here in ADL or Aust.
 

[enut11]

Hi GFWD1D
Please tell me a bit about yourself wrt electronics, professional or hobbyist?
Also what type of equipment do you own and what State/town do you live in.
What do want to achieve wrt Vrefs?
Please send your reply via Personal Messages.
Regards
enut11

[enut11]

Hi I'm new to this forum and would like to know more about your building of V refs.

I'm also interested in the calibration forum that has been set up here in ADL or Aust.

Hi GFWD1D. A good way to start out in Metrology with Vrefs is to build an LM399 based reference. Parts are easy to get and not expensive. PCBs are available from one of our Aussie Cal Club members.
Use a plastic or metal box (better shielding) and download the LM399 spec sheet. This circuit is based on the 'portable calibrator' from the spec sheet. You can power it from a regulated 15v supply (not switch-mode, too noisy) or from a battery (lower noise). Circuit draws about 25mA. The 3 output terminals provide Vz and 10v.
enut11

[VK5RC]

Hi Aus Cal Guys et al.

Sometimes out of a stuff up comes some good. My LTZ references (almost all Kx - Thanks again Ilya) have been sitting in a shelf as part of a longer term experiment- mostly happy - I moved some other test gear a week or so ago and didn't noticed the pile of stuff had moved and pulled out the DC connectors!

I thought it would be good to put it all in a steel enclosure I had spare. It started to grow a bit as a project . I have a linear mains to 18V DC supply which can been seen outside the box in the photo below - labelled PSU1.
The DC is transferred in some shielded twin cable - directly into a small common mode filter box "Filter". Consists of about 2x14 turns (counter-wound) on a ferrite core and a small 100nF cap between the DC rails. The shield is connected to the box - not mains earth. 18V is distributed to secondary low noise linear PSUs, based upon TPS7A4700 - down to 15V for the KX labelled PSU2.

Today quite a bit of time was spent grinding off paint and checking continuity between the panels, rails etc. Common tie point to the shields.
Inside references were well fixed (my favourite 'bodge' attachment method) using double sided sticky tape and zip ties.

Previously I have had some interference from SMPSUs in my DC measurements esp my LED downlights - often in the order of 10-30uV! Today following the 'boxing' it is down to around 1-2uV.

Edit ; grammar.

[beanflying]

Bump 

Collected most of the bits I need. Ali box for the Vishay .005% arriving next week.

Plan is two socketed Max 6350 CPA references powered by 3S LiPo's in the small Ali enclosures with charge and cut out boards (shielded from the reference as well as space allows)

Vishays 2 x 10k, 1x 5k, 2x500R and a 100R mounted as 4W independent resistors so they can be used as a precision divider set. Allows 1-10V in 1Vsteps and 0-5 at .5V or 1-20mA precision currents plus others which suits the accurate temperature logging projects I am working on. Considering adding an additional 2 resistors to this lot yet to generate a few more steps.

Seemingly very accurate Agilent 34401A (2 years out of Cal from a clean room environment)

Might mount the lot into a larger temp stable enclosure at some stage but 3 units suits my limited bench space.

So consider me interested in a swap of some sort in the New Year if it comes up again.

[enut11]

Hi @beanflying
Let us know when you are ready to compare your Ref measurements with ours. We have several DMMs with 6-8 digits.
enut11

PS
I am also into R/C flying. Where do you live?

[beanflying]

SW Victoria in Koroit / Port Fairy area.

Breadboarded one of the Max's this morning. Horrible thing 4.99997V I blame the Temperature it's only 23 degrees

On for 30 minutes now. Top of the chip is 27 degrees and 5.00001V