Ripple DC voltage

Answer 1

When your ripple is a lot lower than the supply voltage, here is a rule of thumb:

for a single diode rectifier: U = I/(100*C) with I in ampere, C in uF

for example 1A supply, 1000 uF cap, gives Upp = 1/100e-3= 10 Volts.

Use 60 for 60 Hz line systems.

for a bridge diode retifier: U = I/(50*C) with I in ampere, C in uF

for example 1A supply, 1000 uF cap, gives Upp = 1/50e-3= 5 Volts peak to peak.

Use 120 for 60 Hz line systems.

Note: it is only an approximation, does not include resistances etc.