Mounting series capacitors on a pcb

[Mp3]

How does one properly solder two capacitors in series to a PCB designed for a single capacitor?

I only have one hole for each capacitor leg and i don't know how to properly mount two capacitors in this fashion. Do i solder one in with some leads exposed and solder to the legs of that?

(I did google before asking, but only found diagrams in schematics, which i understand but don't help me solder properly.)

[Ian.M]

If the pad spacing permits, use axial caps side by side, mounted vertically, with the top leads bent over 1/16" from the body and soldered together.

If its too tight spacing to do that then its going to be a bodge job.  Post a photo of the PCB top and bottom sides, and of the capacitors to be fitted, and give their dimensions and the distance between holes on the PCB, and we can make some suggestions that may or may not include drilling some extra holes off to one side.

OTOH its probably preferable to get one capacitor of the correct value and voltage rating to replace the series pair, or possibly the next lower preferred value and make up the difference with a capacitor in parallel if the value is critical.

[Mp3]

If the pad spacing permits, use axial caps side by side, mounted vertically, with the top leads bent over 1/16" from the body and soldered together.

If its too tight spacing to do that then its going to be a bodge job.  Post a photo of the PCB top and bottom sides, and of the capacitors to be fitted, and give their dimensions and the distance between holes on the PCB, and we can make some suggestions that may or may not include drilling some extra holes off to one side.

OTOH its probably preferable to get one capacitor of the correct value and voltage rating to replace the series pair, or possibly the next lower preferred value and make up the difference with a capacitor in parallel if the value is critical.

Thanks!

It was more for the added smoothing of a decoupling capacitor than to get a value I don't otherwise have. But, if that's the wrong way to go about it, please let me know.

I don't have a problem I'm trying to solve. I have an audio DAC open for repairs and thought while i was doing it that I might as well try to see if anything noticeable happens.

[Ian.M]

Caps in series REDUCES the value: Ctot=C1*C2/(C1+C2).  If you want to INCREASE the value of a smoothing cap (or improve its frequency response) you need to add more caps in parallel.

[Mp3]

Caps in series REDUCES the value: Ctot=C1*C2/(C1+C2).  If you want to INCREASE the value of a smoothing cap (or improve its frequency response) you need to add more caps in parallel.

Yes and i thought if i use two 220's in series in place of a 100 then it's close enough?

[Manul]

There is no benefit here to put series capacitors. Also you will roughly double the ESR, that will make smoothing worse, not better.

Parallel - maybe. Yet, there could also in some cases be a catch. For example, some switching converters require a "window" of output ESR. Parallel nearly halves it. Most often it is safe. Still the question remains are there any audible spectrum frequencies to smooth there? In many cases resistor and active component noise floor is the limit anyway.

[langwadt]

There is no benefit here to put series capacitors. Also you will roughly double the ESR, that will make smoothing worse, not better.

Parallel - maybe. Yet, there could also in some cases be a catch. For example, some switching converters require a "window" of output ESR. Parallel nearly halves it. Most often it is safe. Still the question remains are there any audible spectrum frequencies to smooth there? In many cases resistor and active component noise floor is the limit anyway.

you might want to put two electrolytic in series back-to-back to make a large non-polarized cap

[ledtester]

...

Yes and i thought if i use two 220's in series in place of a 100 then it's close enough?

What's the purpose of the cap? And what's the unit on these 220s? micro-farads, nano-farads, pico-farads? It may not be a big deal.

[srb1954]

Thanks!

It was more for the added smoothing of a decoupling capacitor than to get a value I don't otherwise have. But, if that's the wrong way to go about it, please let me know.

I don't have a problem I'm trying to solve. I have an audio DAC open for repairs and thought while i was doing it that I might as well try to see if anything noticeable happens.

If it just a supply decoupling capacitor it probably won't do any harm just using the larger value cap.