Capacitor Questions

[Jordan]

Does the physical size of a capacitor matter? Like a tiny 16v 1000uf just as good as a large 16v 1000uf?

Also what about voltage? I have a mod that needs 6.3v or 16v caps, but will 25v of the same uf rating work fine?

Thanks

[AK0R]

Re: Capacitor Questions

Does the physical size of a capacitor matter? Like a tiny 16v 1000uf just as good as a large 16v 1000uf?

Also what about voltage? I have a mod that needs 6.3v or 16v caps, but will 25v of the same uf rating work fine?

Thanks

The smaller (physical size) capacitor probably has a *LOWER* temperature rating, which is bad, because it doesn't have as much surface area to dissipate the internally-generated heat. More than likely, it also has a *HIGHER* ESR rating, which is bad, because it will generate more heat due to whatever ripple voltage it sees. In general, you want to use the largest physical size that will fit, while also having low ESR.

A higher voltage rating will work just fine. The capacitor will be physically larger than its lower voltage counterpart, so that will help with heat. Check the ESR rating as well.

[Jordan]

Re: Capacitor Questions

The smaller (physical size) capacitor probably has a *LOWER* temperature rating, which is bad, because it doesn't have as much surface area to dissipate the internally-generated heat. More than likely, it also has a *HIGHER* ESR rating, which is bad, because it will generate more heat due to whatever ripple voltage it sees. In general, you want to use the largest physical size that will fit, while also having low ESR.

A higher voltage rating will work just fine. The capacitor will be physically larger than its lower voltage counterpart, so that will help with heat. Check the ESR rating as well.

The one I have to compare is a OST 100uf 16v 105c RLG cap. Its black with gold writing. Then, I have a smaller one that everything is rated exactly the same, and the colors and stuff are all the same. The only thing thats different is it says RSM rather than RLG. I couldnt find any info other than most low ESR caps are 105c, which both of these are. I also read somewhere that green or black wrapper with gold writing is usually low ESR.

Sound right?

[willawake]

Re: Capacitor Questions

I also read somewhere that green or black wrapper with gold writing is usually low ESR.

not great advice to follow, bad brands like to imitate the colors of the good brands.

check the FAQ, section 3.2 good capacitor manufacturers :
https://www.badcaps.net/forum/showthread.php?t=425

[PeteS in CA]

Re: Capacitor Questions

I've seen low ESR series from UCC in blue, brown, and green sleeving. Some series can be made with more than one color: I've seen KZE parts in brown and green; I've seen LXZ parts in blue and brown. AFAIK, UCC doesn't do color-coding. OTOH Nichicon seems to use brown sleeving on low Z parts that have non-aqueous electrolyte (e.g. PW, PM, PJ, PS, PL, PR series), and black sleeving on low Z parts that have aqueous electrolyte (e.g. HC, HD, HE, HZ, HM, HN series). Panasonic uses blue sleeving on its FC series, which has non-aqueous electrolyte; its FM series, which has aqueous electrolyte, has a black sleeve. All the low Z Rubycons I've seen are in black sleeving and have aqueous electrolyte.

Some vendors do color-coding within their product line, others don't. There is no industry-wide color-coding.

[PeteS in CA]

Re: Capacitor Questions

Be careful in substituting a higher voltage part. You need to be sure the part's impedance is the same or lower than the original part, and that the ripple current rating is the same or higher.

[Jordan]

Re: Capacitor Questions

where can I get data sheets for these OST caps then?

[willawake]

Re: Capacitor Questions

why would you want OST datasheets? their products are crap and prolly working well out of specs after a while. just substitute a recommended brand like Panasonic, Rubycon, Sanyo choosing their low esr series and substituting a value/voltage equal to or slightly higher and end of story, the board is working fine.

[Jordan]

Re: Capacitor Questions

Alright will do. Didnt realize OST was that bad. DFI uses them on their older boards (nf2) and no one has ever complained about DFI's caps....