Not real familiar, just usually installing a device, but got me interested how it works. So would both be combined in a converter device? Seems that it might be an important factor if troubleshooting. Such as LV DC exterior lighting.
Google half wave, full wave, and full wave bridge rectifiers.
Capacitors are used to store some energy when the AC wave is rising, then release that energy as the AC wave is falling - to make a straighter line that represents the DC output. That capacitor still will cause a ripple in the output if only a simple half wave rectifier compared to if used with a full wave bridge.
Bridge circuits can be made for three phase input/ DC output as well, that is what you have on forklift chargers and other higher power applications, and is what the "front end" of a three phase input VFD basically is.