Question about power supply filter

[rutledj]

What is the reason for the first cap filters values being 100uf while the rest are 47? Need a little refresher with ps theory.

Thanks,
Rut

[Bob-I]

What is the reason for the first cap filters values being 100uf while the rest are 47? Need a little refresher with ps theory.

Thanks,
Rut

Actually the filters are usually made up of 2 caps in series so the value is 1/2.

The first stage removes most of the AC ripple. The second stage removes some more but more importantly it decouples the node from the previous node, so modulation of the rail at the first stage won't affect the second.