On Paper: Regulator in the Context of a Power Supply

Regulators are used after the power supply has been converted to DC from AC. The regulator requires capacitors to create a current that the regulator will accept. The lowest portion of voltage on the input waveform must be the consideration for the lowest voltage acceptable to the voltage regulator to get the output voltage needed for the circuit. The 7805 voltage regulator requires a .1 uf (microfarad) capacitor helps transient response.