Answer 2—For a given load, a larger capacitor will have less voltage droop between the AC peaks, and will therefore have a narrower conduction angle through the rectifier. This will degrade the power factor of the power supply and increase the conducted emissions.

A larger capacitor will reduce the ripple voltage at the input of the regulator and raise the average voltage. This increases the average power dissipation in the regulator.

Contributor: David Tweed