Originally Posted by
Mrs. SewNSew
If they are meant to balance out the energy...isn't modern day electricity delivered in a more evenly balanced fashion?
The capacitors aren't just there for the line voltage coming in from the power company, that's really a very small part of it. The majority of their purpose is on the internal side of things where as the electricity is moving about it causes fluctuations on the internal power of something (the power being provided by a power supply in the machine which gets its power from the plug in the wall).
More modern electronics are actually much more fraught with issues due to noise on power systems and noise on signals. This is because more modern equipment generally has lower voltage supply so the "margin for error" is also smaller. Additionally, as signals get faster, the sudden change in direction of signal gets faster and the noise is greater. Modern electronics have many, many capacitors in them of several different values, depending on their purpose, how much power or noise or the frequency they are being used for.