computer grade elcaps

[jarthel]

I was looking at the mouser catalog and found this. I read the datasheet and they are advertised as long life, high CV and current filtering (which I assumed meant the ripple current rating for this cap is high).

I got no idea what CV meant so some searching led me to believe it means the charge of the capacitor.

Anyway, that's not the reason for this thread.

As I said I was looking at mouser and they seemed to be more expensive than the snap-in that I was looking at.

Can someone tell me what is so special with computer grade caps? I compared the specs of a snap-in cap VS a CG cap (both from Cornell Dubilier) and the snap-in cap has longer rated life and the ripple current rating is higher.

maybe they are not special at all?

thank you for the reply

ps. I did search the forums but all I cannot discussions comparing computer grade caps with other type of elcaps. I also searched the net but all I can find is some history on the name "computer grade" caps. The rest of the search results are mostly shops selling these caps.

[h_a]

Honestly I don't know, but I think this is merely a term for cheap caps having quite ok quality.

Cheers, Hannes

[jacco vermeulen]

BullS...

[AndrewT]

Hi,
looks like we should ignore the names applied to cap types and instead read the specs for all models from each and every cap manufacturer.

[mzzj]

CV= capacitance per volume.

[jarthel]

Originally posted by mzzj
CV= capacitance per volume.

thank you.
==============
but those new Cornell-Dubilier 381LX are really small for the capacitance they carry.

maybe in te old days, "computer grade" caps = high quality but not these days?

[jacco vermeulen]

Computer grades have high ripple values, low leakage current values, generally have high voltage surge values.
Ultimately boils down to high reliability and a long life expectancy.
Some capacitor manufacturers did/do not use the term Computer Grade, but label their electrolytics as Long Life grade, the ones by Rifa and Siemens/Epcos for instance.
Most buy NOS big can CG's at really affordable rates, if you check the retail prices of the big bottles you'll find out they're pretty steep, $125 for a single big boy cap is not uncommon.
A couple of years ago i bought a large number of factory fresh 12-can CG boxes, turned out they couldn't handle the surge values of the big computer powersupplies they were ordered for.
The company had to dump a containerload of these caps because of the design mis-judgement.
Downside is that those CG's measure 9" in length, 3" diameter and weigh 2lbs each, good for constructing very sizeable amplifiers only.

[Luke]

Is it ok to use these big Computer Grade Caps if they are like 10 years old?

[AndrewT]

Hi,
the least you should do is reform them.
It would take a fair bit of kit and knowledge to test whether the ESR has deteriorated.
I believe reforming does not bring back ESR, only restores spec leakage.

[ssmith]

Originally posted by Luke
Is it ok to use these big Computer Grade Caps if they are like 10 years old?

depends if they're used, and how they have been used. Once you figure this out you can refer to the datasheet for that particular cap and compare against the lifespan specs.

do a search also here to look for reforming caps that have been sitting on the shelf unused for a long time. This is a subject that has been addressed here before.