Filtering Capacitor for AC

Duncan Amp Tools PSU Designer II is a nice little free program for simulating power supply design. It even takes into account transformer regulation, which is helpful in designs using small transformers that are poorly regulated. All you have to do is spec the rated voltage, measured no load voltage, and VA rating. Then change the circuit blocks to what you need (half wave, full wave, doubler, etc) and change the filter cap values and load current values to whatever you want.

PSUD2