I found a circuit that can be used to provide power from mains AC to various DC loads and I'm having trouble understanding how it varies the output voltage depending on the load resistance.
It seems that the RC subcircuit that preceeds the rectifier and the output RC subcircuit are interdependent because their waveforms change drastically when changing the load resistor.
How can the output voltage be represented mathematically?
To facilitate a more detailed discussion, consider adding a unique reference designator to each component.
At 60 Hz, each capacitor has a specific impedance. For a simplistic analysis of the circuit, replace each capacitor with its equivalent 60-Hz-resistance. Next, combine any series and/or parallel resistances into their equivalent single-resistor value. Then, with Ohm's Law, you can calculate the voltage drops throughout the circuits as the load resistance changes.
Note that because the input AC is full-wave rectified, the frequency seen by the 47 uF cap is 120 Hz, not 60 Hz. Actually, the frequency spectrum of a full-wave rectified sinewave is more complex (!) than that (you can see this in the very distorted current waveform), but for this analysis it is close enough.
To facilitate a more detailed discussion, consider adding a unique reference designator to each component.
