Oil for a leaking Tinsley standard resistor

[tggzzz]

The remainder will almost certainly end up being used (sparingly and only!) on kitchen chopping boards.

Your resistor will get lonely, so you should keep the spare oil for its siblings.

[Gyro]

Well they did have a couple of old Cambridge Instruments ones, with brass tops and nice shiny Copper horns. From the leaks and loose bits though, they had already drunk more than was good for them!

They were definitely pre-1948* too. No model numbers or current rating markings either. That's why I picked out the dull looking Tinsley.


EDIT: *For the casual reader, before 1948 the 'International Ohm' definition was artifact based, based on a Mercury column of standard area / length and mass, at 0'C. After 1948, the 'Absolute Ohm' was adopted. Hence OHMS (ABS) on the Tinsley unit.

[Alex Nikitin]

After leaving to settle for a couple of days, I thought I had better check the insulation resistance of the Liquid Paraffin - now that's something that I really should have done before I poured it in!.

My curiosity won and I've ordered a bottle of the same Bell's Liquid Paraffin BP. A "quick but not dirty" experiment with two bare wires in a polyethylene cap showed that without oil the leakage of the setup was about 50fA at 100V (the box fixture with the BNC connector, cable and BNC/Triaxial adapter leaks less than 10fA at 100V so there was some added leakage  ), or 2Pohm , with the cap filled with the oil, as on the photo, the resistance dropped to ~300Tohm. Not perfect but good enough for most purposes. 

Cheers

Alex

[Gyro]

That's somewhat better than I had expected, especially just out of the bottle without specific drying, although that's probably part of the product preparation [Edit: or just the distillation]. Certainly enough to allay any remaining fears around normal value standard resistor filling (thanks). You now appear to have a little more laxative remaining than I do.

I wonder about using it for creating a more isothermal, and stable, environment for voltage reference, nulled circuits etc. It's certainly a lot easier to handle and clean up than Silicone oil.