Products > Test Equipment
High voltage oscilloscope probe
jonpaul:
P6015 requires Freon 114 fill with specific gas/liquid properties. With no freon, it works to 20 kV. \
The Freon usually Leaked out of the seals after some time and needed a recharge. The clear ring at the P56015 tip allowed Freon liquids level to be checked.
P6015A has a silicon insulation thus no gas.
yes the tip capacitance is just a few pF so any metal near the tip will degrade the pulse response.
Jon
Hydron:
I recall some people suggested that butane was the closest readily available option to the original P2015 freon (albeit at a somewhat higher vapor pressure) - has anyone here tested it? P2015s are a lot cheaper to come by than P2015As.
Obviously if you do push it to the breakdown point an over-pressure+arc event with butane is worse than with freon, but you're probably in a pickle regardless if you're dumping enough energy to blow up the probe in the first place.
My P2015 actually came with a bit of Freon left in the can (hopefully enough for a charge or two), I've kept it (in the fridge) unused though as I need to replace the probe seal before re-charging it with unobtanium gas.
jonpaul:
Hello again
I was super lucky to find a mint P6015A in orig case/access plus several probes/comp boxes/clbes lose at a Ham fle I think....
Far superior to P6015.
A P6015 depends on the dielectric constant of the F114 gas and the boiling point and vapro pressure as well.
The liquid charge of perhaps 12 mm at the tip held dow creates the gas in the proble body.
Other gases/liquids will not have the correc Dielectric constant nor vapor pressure.
Finally Butane is highly flammable and a fire/explosion hazard used areoun high voltage.
The freon cans go deal gradually and you need a certain amount of the freion to properly charge the P6015.
A P6015 withoyut Freon and just air works OK but only to 20 KV.
Stt eh TEK manual on this point.
Finally P6013 is a smaller, older model that has no freon and goes to 15..20 kV.
That is a low-cost alternate.
Enjoy,
Jon
Hydron:
I'm pretty sure that the probe does not depend on the dielectric constant of the freon - only a small amount is in liquid form, and the vapor will not be dense enough (IIRC, something between 2 and 3 atmospheres) to have a dielectric constant appreciably different to 1. I'll admit couldn't find the actual number for CFC-114 specifically, but all other gases I did find had STP dielectric constants values within 1% or so of 1 (as expected for their low density). The gas is in there solely to raise the breakdown voltage (through both having a higher dielectric strength than air, and also by being at an elevated pressure).
The point about it not being ideal to have a flammable gas is a valid one though (note that CFC-114 apparently forms phosgene when exposed to flame though!) - my main concern about using butane would be a leak igniting.
alm:
--- Quote from: Hydron on January 16, 2023, 09:03:47 pm ---I'm pretty sure that the probe does not depend on the dielectric constant of the freon - only a small amount is in liquid form, and the vapor will not be dense enough (IIRC, something between 2 and 3 atmospheres) to have a dielectric constant appreciably different to 1.
--- End quote ---
It depends on the dielectric constant filled with the freon and filled with just air to be approximately the same, so it can compensate to both conditions. So if you fill it with something that produces a dieletric constant substantially different from 1, like silicone as in the P6015A, or a liquid, it will fail to compensate.
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