Products > Test Equipment

Fun With Low Leakage/Bias Current: Femtompere, Electrometer, Keithley 617

<< < (73/82) > >>

MiDi:

--- Quote from: unseenninja on April 07, 2024, 03:34:46 pm ---I was very pleased to discover that Mouser sell H&S G_02330_HT cable by the metre. I trust cables made by me much more than I trust used, overpriced cables from eBay. They will most likely be far better than the Pomona cable I'm using at the moment.

--- End quote ---

The H&S G_02330_HT has PE insulation, which is not the best for low current measurements (leakage & DA).
Could be hard to find a matching triax connector for that outer diameter.
For reference: my DIY triax cable.

Alex Nikitin:

--- Quote from: MiDi on April 07, 2024, 04:28:09 pm ---The H&S G_02330_HT has PE insulation, which is not the best for low current measurements (leakage & DA).

--- End quote ---

Believe me, from experience, H&S uses a VERY GOOD PE, at room temperature even at 100V leakages are essentially unmeasurable for several meters of cable, plus noise levels from cable movements are very low, you almost can forget that you are dealing with femtoamps... .

Cheers

Alex

unseenninja:

--- Quote from: MiDi on April 07, 2024, 04:28:09 pm ---
The H&S G_02330_HT has PE insulation, which is not the best for low current measurements (leakage & DA).
Could be hard to find a matching triax connector for that outer diameter.
For reference: my DIY triax cable.

--- End quote ---

They do quote 100 TΩ insulation resistance in their data sheet. I'm hoping that matching connectors won't prove to be a problem, but I'll know more when I have the cable.

I was tempted by the Lemo cable that you used, but the 10 metre minimum order kind of put me off as I have no idea what I would do with the remaining 7 metres.

Alex Nikitin:
I’m using H&S triaxial cable here, for 1.5m length  with two Pomona connectors, and 100V bias, the leakage is below 10fA (let’s say, it measures about 5fA and if I remove the voltage it shows about 3fA).

Cheers

Alex

unseenninja:
Ah, so you got the Pomona 5056 connectors to mate with the G_02330_HT cable successfully?

The dimensions don't quite match, but I suspected it was possible to use them with the slightly thinner cable. I thought I'd use Marco Reps' method to heat up the outer insulation to get it stretch a bit more to accommodate the cone. A wrap of self vulcanising tape around the outer insulation should provide some strain relief when the connector is finally tightened.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod