Cap leakage

Nov 09, 2011 7 Replies
J

I had to buy some BP/NP caps today "16V 470Uf" and the pickings were slim. In fact, I was looking for a Axial package of that value and could not find any one that had stock of that type or even list it.



So I ended up getting some Radial types from "NICHICON". "CHicago Capacitor" wanted a min or of 3k pieces at .98 etc, we only need 150 but at least they were willing to make them. But back to what we ended up ordering.



I notice the leakage was up around 320ua or something, isn't that kind of high ?



I am not really worried about that because of where they are being used, which won't get effected by this but really, it just seems high.



Jamie


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J

Hi, Jamie-

How long did you test the leakage? Try allowing the cap to sit with applied voltage for a while and the measure. Let us know how that goes.

Cheers, John S

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J

I have not tested these, its just data I saw at mouser today while I was ordering. I was just shocked at the leakage of the BP's compared to polarized versions.

I think mouser must have a miss print..

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and from the MF.
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Leakage looks good from the MF.

Jamie

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P

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** The figures are exactly the SAME !!!

Dickwad.

.... Phil

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L

I do have 80 of the Nichicon 25V 470uF, they were probably less than

25 cents each.

I don't know where you are looking, but these Panasonic 16V 470uF are

22 cents per 100.

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P

"linnix"

I don't know where you are looking, but these Panasonic 16V 470uF are

22 cents per 100.

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** Err - the OP was on about BP / NP caps.

They are more expensive than polarised ones.

.... Phil

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S

Leakage for regular e-caps is 0.01 or 0.02CV. Special low leakage caps (not well stocked in North America, especially in larger sizes) are about 1/10 of that (0.002CV, frequently). Those particular BP ones are

0.03CV. Not a huge difference from the regular ones.

CV is nominal capacitance * rated voltage to get leakage at rated voltage after some period of time. Typically there's also a minimum that comes into play for smaller capacitances.

Actual leakage can be quite a bit lower, and varies quite a bit between different constructions and suppliers, but not so much from part to part of a given construction.

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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