Once AC has been rectified, do I need a capacitor to filter out ripple?

Question

Once AC has been rectified, do I need a capacitor to filter out ripple?

Answer 1

Yes, otherwise you get pulsed DC.  The more current you want to pull, the larger the capacitor, a few thousand microfarads is common for a few amps.

Answer 2

Yes, otherwise all you have is a pulsesating DC signal. you then need a capacitor to hold the volatage up, and elimanite the pulses, to a set DC voltage.

Answer 3

Depends on what you are going to use the supply for.

For charging a battery, lots of ripple is OK.

for most other applications, you want the ripple minimized, for which you need a large capacitor. Note that it will not be completely gone unless you use a huge cap. But a regulator of some sort will reduce it to close to zero.