Originally Posted by replaytv
I didn't think there were any electrolytic capacitors on the motherboards. I thought they were mostly used in power supplies because many have polarity sensitivity the precludes them from being used in audio and video applications that have AC applied to them.
Generally you'll find them as extra filtering for the DC right next to the pin on a chip where the power goes in, usually denoted as Vcc, and sometimes they'll be used for signal coupling between stages as well, where the signal itself is an AC-type waveform, but it's really varying between ground and the DC supply voltage, and it needs decoupling from the DC before moving on to the next stage, or an output needs an AC bypass around the transistor doing the amplifying.
That sort of thing existed way back in the vacuum tube days.
If you ground one lead of a capacitor, then AC gets shunted through it, and that's a parallel connection, but you can also put them in series between one stage and the next and an AC waveform will go through them.
On computer motherboards you'll find them clustered around the CPU, because nowadays there's a whole extra switching supply right there to handle the various voltages needed for various sections of the CPU (and maybe even for the RAM).
In fact it was BX chipset motherboards (Pentium II and Celeron) that were early victims of "capacitor plague", he muttered bitterly.