adding ceramic caps in parrallel?

[WeStSiDePLaYa]

Im wondering if it is beneficial to add small SMT ceramaic capacitors on the output side of a psu in parrallel with the electrolytic capacitors. I have read that this may extend their lifespan as they will not need to deal with as much high frequency ripple current.

i mean its an easy enough thing to do, but is it worth it?

[kc8adu]

Re: adding ceramic caps in parrallel?

cant hurt.i do it to mobo's that i overclock.often tantalums and mlcc at each vrm cap.

[yanz]

Re: adding ceramic caps in parrallel?

smt caps aren't available here. perhaps you can reccomend what is the value of caps (ordinary ceramic caps) i can use?

[999999999]

Re: adding ceramic caps in parrallel?

Small ceramic caps will reduce the high frequency ripple, but typically are not of high enough mfd value to do any substantial decrease in ripple current, not enough to save the life of an electrolytic that would otherwise have problems.

Further, the electolytic doesn't even respond to this higher frequency, the impedance is too great at HF for 'lytics. Ceramics are best used as decoupling for the powered IC. If you wanted something to combat ripple current in the 'lytics, either another 'lytic or solid cap would be in parallel such as a tantalum, organic or other solid core type. They are rather expensive though (in larger sizes more effective), and usually unnecessary. Simply using a good quality, large 'lytic is sufficient unless the ambient temp is very high.

However, limiting HF with a ceramic at this end of the wire harness is of limited benefit, it would do far better to put same caps on the other end, on the mainboard or other powered equipment, and yet, where they are needed they often already exist on the other end (equipment). If the wires are traversing an area where they pick up very high frequencies and the equipment on the other end is susceptible to this, it might help to put ceramics across each wire (rail just before the wire) at both ends, but this is more often for analog circuits, digital are more tolerant.

[yanz]

Re: adding ceramic caps in parrallel?

ho, another powerfull newbie thanks for your input...