In a regulated power supply, the output of the electrolytic filter capacitor is connected to the:

A standard regulated power supply is built in stages: a transformer to step down the voltage, a rectifier to convert AC to pulsating DC, a filter to smooth the pulses, and a regulator to stabilize the voltage. The electrolytic filter capacitor is responsible for the smoothing phase. Once the pulsating DC has been smoothed into a more steady, albeit unregulated, DC voltage by the filter capacitor, this output is fed directly into the voltage regulator. The voltage regulator's job is to maintain a constant output voltage despite any variations in the load current or the input voltage. Distractors like a pi filter or matching circuit are incorrect because the regulator is the specific next sequential component in a standard regulated supply architecture to ensure voltage stability.