Author Topic: FS (UK/World) 7 decades (10K to 10G) resistor set.  (Read 4944 times)

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Offline Alex NikitinTopic starter

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #50 on: August 24, 2024, 10:44:22 pm »
Three more boxes (with a silver plated BNC shorting plug) are available (one from the photo is already going to be posted on Monday).

Cheers

Alex
 

Offline guenthert

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #51 on: August 25, 2024, 08:34:49 am »
   I received an unit well packed and better made.  The listed values (on the bottom, to discourage cheating ;-) near perfectly matched my measurements using my Datron 1271 (up to its maximum range of 1GOhm), the ones of the high value resistors matched closely my measurements using my Keithley 617.  Neither of my instruments had been calibrated in the ~7 years I own them and probably not for a much longer period.  I had already good reasons to suspect that my Datron was more accurate than I could reasonably hope for, but I had no idea that the Keithley was so close (well, within specifications, which of course became meaningless decades ago).

   I used multiple of those resistors to validate the linearity of the Keithley 617 (validating the linearity of the Datron 1271 is beyond my skill and means, I'm afraid).

   Imho a neat tool for those interested in high resistances / low currents.
 
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Offline guenthert

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #52 on: August 25, 2024, 08:41:23 am »
    Re: BNC->4mm terminals:  in my collection of adapters I found a no-name unit and using a Keithley 617 measured it's insulation between conductors to be around 129GOhm (probably should clean it and re-measure, but I don't have pure alcohol readily available -- the content of the bottle I had completely evaporated during the last five years). 

   I also found a Ponoma 1296 which clocked in at a whopping >500TOhm.  One gets what one pays for, I guess.

EDIT: My Keithley 617 is suffering from excessive input bias current and awaits repair; readings of >1TOhm are highly suspect.  Still I'd think the isolation of the Ponoma to be much higher than of that no-name adapter referred above.
« Last Edit: August 31, 2024, 07:36:07 am by guenthert »
 

Offline Hydron

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #53 on: August 25, 2024, 11:55:05 pm »
My own bad adapter turned to be worse than I though, but putting 1100V (hitting the 10mA limit, actual voltage unknown but probably a few W dissipation) across it seems to have burnt the worst of the leakage away >:D
(it's still not amazing, but was leaking milliamps when you turned up the voltage up beyond a few hundred V earlier, now just in the ~1uA range @ 1kV)
 

Online krish2487

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #54 on: August 29, 2024, 01:54:19 pm »
@Alex Nikitin
My apologies for the lack of a follow up response until now.
I had a few pomona 1296 on order and I was waiting for them to show up.
And I m happy to report on my findings! :-)
The same test setup as before, plcs, settling time and the 4W measurement method suggested by you.
These are what I measured on the 34460A

Measured                               Marked on the back of the unit
9.99991K                                9.9997K
99.9939K                                99.994K
1.00038M                               1.00038M
10.00344M                             10.0032M
100.4514M                              100.4M

So pretty much spot on! :-) Unfortunately I cannot measure greater than 100M on any of the meters I have with me..
If god made us in his image,
and we are this stupid
then....
 
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Offline guenthert

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Re: FS (UK/World) 7 decades (10K to 10G) resistor set.
« Reply #55 on: August 30, 2024, 09:10:09 am »
[..]
Unfortunately I cannot measure greater than 100M on any of the meters I have with me..
   You could place the meter in voltage function with 10MOhm impedance and use it as a voltage divider with the DUT, then apply a known (preferably high) voltage.  The internal "10MOhm" resistance varies wildly in cheap hand-held DMMs, but should be fairly close to nominal in a bench meter.  Don't expect ppm accuracy, but closer than 0.1% (which you can verify with the 10MOhm resistor as DUT you measured earlier).
« Last Edit: August 30, 2024, 09:12:51 am by guenthert »
 
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