Just a trivial question about capacitors.

[beppe61]

I have a basic question on capacitors size.
I have two capacitors: one 6800uF/100 V and another one 4700uF/100V.
So pretty similar in electrical specs.
The first is more than 4 times the second in volume.
How is this possible ?
Thank you very much indeed.

Kind regards,

beppe

[DorinD]

Maybe the first one is a smooth-foil "audiophilic" one? Like this Visaton but of higher voltage:

http://www.visaton.com/en/chassis_zu...ial/index.html

[beppe61]

Originally posted by DorinD
Maybe the first one is a smooth-foil "audiophilic" one? Like this Visaton but of higher voltage:

http://www.visaton.com/en/chassis_zu...ial/index.html

To be more specific the big one is from SIC-SAFCO and the other is from Kendeil.
Both are of the aluminum electrolytic type.
This difference in dimension is just huge.
The 1st comes with screw terminals and the other one with terminals to be soldered.
Could this be the reason?
I have notice that screw terminal caps are usually much bigger for same values.
The following question of course is: what does this mean in terms of performance?
I believe the bigger one is better but I do not know why.

Thank you and kind regards,

beppe

[pinkmouse]

The bigger one is most likely designed for higher ripple currents.

[jacco vermeulen]

higher surge values, the French Sic-Safco capacitor is a computer grade type. (FELSIC)
105C, Long Life, L'Audiophile had them in their designs(could also be bought in their Paris Maison de L'A. shop, used to be pretty expensive.

[beppe61]

Originally posted by pinkmouse
The bigger one is most likely designed for higher ripple currents.

Thank you very much for your kind and valuable reply Sir.
As I understand that ripple current is a such a fundamental value it is a pity that to get it one have to seek for the relevant datasheets, when they are available.
It is not printed on the cap I mean.
In the future I will select caps mainly on the basis of their dimension (and of course the rated working voltage and brand).

Thank you very much again and kind regards,

beppe

[jacco vermeulen]

Originally posted by beppe61
it is a pity that to get it one have to seek for the relevant datasheets, when they are available.

Presto ( ) :
www.sicsafco.com/overview/overviewfelsic.html

[beppe61]

Originally posted by jacco vermeulen


Presto ( ) :
www.sicsafco.com/overview/overviewfelsic.html

Thank you so much Mr. Vermeulen !
My further point is: why not to print on caps the max working voltage, max working temperature and current ripple instead of the uF ?
I mean, max working voltage and max working temperature being the same, a 3300uF could actually have a current ripple double of that of a 6600uF of different brand/series.
Is this not worrying ?
From what I have learned here current ripple is a very fundamental value for a cap, maybe more important than capacitance.

Am I wrong?

Thank you and kind regards,

beppe

[jacco vermeulen]

Originally posted by beppe61
why not to print on caps the max working voltage, max working temperature and current ripple instead of the uF ?

Paper is easier to read than capacitors.

Printing extra costs money ! Capacitor producers generally do not produce for diy persons, but for commercial purposes.
A designer may be interested in a lot more data, depending on the application; ESR,ESL, or Longevity values.
For one application the size may be of importance, for an SMPS or a frequency converter it may be the speed of a capacitor.
A commercial enterprise will try to choose the cheapest solution that meets the minimum requirements.
I think it's far more easy to finger through a catalogue than juggling a bunch of caps. (unless you plan to join a circus)
Nowadays it's so easy, just download complete capacitor catalogues from the manufacturer. When i started this hobby i had to use every resource to get my hands on paper data, try laying your hands on a Rifa catalogue in 1985.
For most applications the voltage and capacity ratings are the primary data of interest, the max temperature secondary. For most capacitor uses the surge and ripple values are of minor interest. Mass produced audio components have horrible capacitors.
That's where the knowledge of a top notch audio designer comes into the picture, i'm astonished by the hardware knowledge of people such as Nelson Pass and the other audio VIPs on this forum.

[beppe61]

Originally posted by jacco vermeulen


Paper is easier to read than capacitors.
Printing extra costs money !
Capacitor producers generally do not produce for diy persons, but for commercial purposes.
A designer may be interested in a lot more data, depending on the application; ESR,ESL, or Longevity values.
For one application the size may be of importance, for an SMPS or a frequency converter it may be the speed of a capacitor.
A commercial enterprise will try to choose the cheapest solution that meets the minimum requirements.
I think it's far more easy to finger through a catalogue than juggling a bunch of caps (unless you plan to join a circus).
Nowadays it's so easy, just download complete capacitor catalogues from the manufacturer.
When i started this hobby i had to use every resource to get my hands on paper data, try laying your hands on a Rifa catalogue in 1985.
For most applications the voltage and capacity ratings are the primary data of interest, the max temperature secondary. For most capacitor uses the surge and ripple values are of minor interest.
Mass produced audio components have horrible capacitors.
That's where the knowledge of a top notch audio designer comes into the picture, i'm astonished by the hardware knowledge of people such as Nelson Pass and the other audio VIPs on this forum.

Dear Mr. Vermeulen,
your excellent and very interesting reply gives me the opportunity to put some other questions.
Let me please quote some of your statements.

"A designer may be interested in a lot more data, depending on the application; ESR,ESL, or Longevity values"

I understand perfectly your point.
A designer need to know all the picture.
Anyway I suspect that a value "fundamental" like the ripple current could be adopted as an indicator of the intrinsic quality of the cap. And maybe also related to the other characteristics like the ESR, ESL and even the longevity.
I mean, a high ripple current cap is a high grade cap in general.
And the price follows, as usual.

" Mass produced audio components have horrible capacitors "

And I think it is a pity because basically good design can be let down by skimping on some "fundamental" components, like I think filter caps in the PS are.
All right, they can be expensive but still they are fundamental.
Better to save in other ways.
On this basis I think that the so-called "recapping" should be "always" beneficial and worthwhile.

" I'm astonished by the hardware knowledge of people such as Nelson Pass and the other audio VIPs on this forum "

Me too. Moreover I am even more astonished by the kindness of these famous designers in sharing their precious know-how for free.

Thank you so much again and kind regards,

beppe