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Polypropylene Capacitors with Polarity?
#1

I'm looking for some input on this:

https://www.youtube.com/watch?v=BnR_DLd1PDI

Is polarity on these newer caps a valid concern and a benefit to test them and install the "correct" way?

Thanks,
Rich
#2

I wouldn't call it "polarity", it would in electronics tems imply the DC polarity, but indeed this might have some effects.
In the radios we are dealing with, given the size of modern caps which is much smaller today, I doubt you will notice any appreciable increase in noise or anything else.
In circuits where a pickup of small signals is the purpose and the input impedance is high this might matter.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

If you had asked me sometime ago I would have said no but after watching that video and giving it a try on my last couple of re-caps I can honestly say the noise and hum level is noticeable lower. To me it makes a difference and I now install all caps with the outside foil as it was originally in the radio.

Gregb
#4

There is also a fellow of Y.T that posted a rebuttal to the idea that non electrolytic caps had a polarity, Dennis Carter is the guy's name. In any event he explains, and shows why the test employed is not really valid, and explains why they don't denote the outside foil anymore on the body of the cap. I myself haven't really noticed a difference, other then the fact that the original caps are all leaky, so it would be impossible to tell anyhow. I've noticed that in many old radios they didn't even observe which end of the cap was connected where, the end with the line is supposed to be connected to the terminal that is closer to ground potential, but they often ignored the line.
Regards
Arran
#5

Thanks for the input guys  Icon_smile I think I'll go ahead and try this.  I figure it won't take long and can't hurt anything.  The only way you'd know if it matters or not is to install them all 'backwards' and try it out, then install them all the 'right' way and compare.  Not going to do that  lol.

Hey Arran - what is "Y.T"?

Rich
#6

I think Arran is referring to YouTube?

--
Ron Ramirez
Ferdinand IN
#7

Ah...got it.  Thanks Ron  Icon_smile
#8

(03-22-2017, 09:45 PM)criageek Wrote:  I'm looking for some input on this:

https://www.youtube.com/watch?v=BnR_DLd1PDI

Is polarity on these newer caps a valid concern and a benefit to test them and install the "correct" way?

Thanks,
Rich

I have heard it said that this can be an issue and have read how to use a capacitor tester to determine the outer foil. The article stated that the outer foil should always go to the ground or to the low side of the signal. The article was in an audio magazine and audiophiles can have some peculiar ideas. I did try their method and never discovered a spec of difference.




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