PIO caps question

[EC8010]

Good grief! You have a chassis big enough to contemplate >0.1uF? I normally try to redesign to make 56n useable!

 

[rdf]

Here you go:

http://search.ebay.ca//search/search.dll?from=R40&satitle=teflon+capac*

Higher thn 0.1 uF is rare and I've never seen new. To my ear:

- Orange Drops are OK but don't compare to the Teflons.
- Can't stand Wima MKP.
- Audicaps do a nice job.
- Like some old Philips polycarbs and TRW polystyrene.
- K40y-9 PIO's are wonderful down low and go completely awry up top.
- Cuban maidens rock

 

[Tubesin]

I made a simple test to check the leakage of the capacitor as follow, run a high voltage from the power supply after the filter, attach the cap in one side and the other with a 100k resistor to ground and measure the joint point with a dvm. And I found that leaking in oil caps are usually 10 times more than the plastic caps (like rtx cap). The oil caps leaks in the order of 0.52v over 394v and the rtx leaks 0.014v over the same 394v!!!! Do this kind of test a safe and reliable one?

 

[EC8010]

It's as good a test as any. And since you now know the voltage across 100k//10M (DVMs are all 10M input resistance), and you know the applied HT voltage, you can calculate the leakage current through the capacitor. Having done that, you know the voltage across the capacitor and the DC leakage current through it, so you can calculate its leakage resistance at that voltage.

 

[anatech]

That's how I do it when the part is not able to be powered up in the chassis.

-Chris