what best caps 4 PSU

[predator0357]

I need advice wich one is the best for PSU?
The caps are:
4700[uf] 10[V]

2200[uf] 10[V]
The brands for the 2200uf:rubycon yxf, NCC kmg or kze.

[goodpsusearch]

Re: what best caps 4 PSU

kmg are general purpose.

YXF are low esr but maybe not low enough for psu, depending on the original caps it used.

KZE should be good.

[Pentium4]

Re: what best caps 4 PSU

We've already responded in your other thread. My favorites are Chemi-Con KY and nichicon PW

[budm]

Re: what best caps 4 PSU

Do not forget about the ripple current rating that needs to consider beside the brand, ESR, size, etc.

[PeteS in CA]

Re: what best caps 4 PSU

While you can get away with not understanding the parts and the circuit if your replacement part is the same brand and series, you really should understand the parts and how they are used in circuits. Understanding will make you better at doing technoid stuff.

Electrolytic capacitors are used for different purposes. The four main purposes in power supplies and computer motherboards are input side smoothing, output side smoothing, storing and supplying energy for PWM start-up, and noise decoupling.

Different series of electrolytic capacitors are designed to have certain characteristics. Parts rated for 85C are usually general purpose or 50/60Hz smoothing. 105C rated parts may be high temperature general purpose, or they may be of one of several grades with high ripple current and low impedance ratings. Usually the manufacturers' datasheet will tell you for what a particular series is best suited.

So, 85C general purpose parts are suitable for decoupling. This is not a very stressful application, and general purpose parts are adequate, and probably less expensive. If you are repairing something, replacing 85C parts with 105C parts will probably improve reliability, with minimal (if any) extra cost. You just need to match the capacitance rating, voltage rating, and case size.

With the 200V-400V input smoothing application, usually matching the temperature, capacitance, & voltage rating and the case size will result in matching the ripple current of the original part. Different brands tend to have equivalent series, so other than using a good brand, brand doesn't matter much. These parts don't fail very frequently, so the chances that the original series (and equivalents) are obsolete by the time you need to replace some is pretty high. And what is available are likely to be higher capacitance and ripple current. But that's OK. If the original parts are rated for 85C, definitely get 105C parts. Beyond that, match the case size and voltage rating. If the capacitance is higher it will probably make the power supply more robust in handling power brown-outs and drop-outs.

PWM start-up requires a fairly low impedance part, as it has to deliver a fairly good burst of energy without dropping the DC voltage very much. Thus the part used should be at least as good as a Nichicon PW, Panasonic FC, or UCC LXZ series part. If the manufacturer used a general purpose part, that's poor design, and if it's an 85C part, that's pathetically poor design. In my opinion, of course. For replacements (and these parts do fail fairly often), use the series I listed, or series such as Nichicon's HE or HD, Panasonic's FM, Rubycon's ZL, or UCC's KY or KZE series. These series are the next couple of steps better in terms of impedance and ripple current.

Output side smoothing is probably the most stressful application, and low impedance and high ripple current rated parts are a must! And understanding and matching the characteristics of the original parts (or maybe getting a little bit better) is a must. There was a time when vendors had just one or two low impedance series, and that was what was used. Nowadays there are multiple series, and in some applications (e.g. motherboard VRMs) the very best are a must! So output smoothing parts need to be selected carefully (assuming you have a good variety of series available, of course).