I have two circuits that I am trying to connect. The first is powered by a 5v AC supply. The second circuit needs 5-9v DC. What can I do to convert the 5v AC supply for my needs?
you could use Greatz bridge like this in the attached picture... it's a full-wave bridge rectifier and instead of building it from 4 diodes, you can buy a ready made bridge with 4 pins and 4 built-in diodes...
the capacitor needs to be larger if you need more current... it serves to smooth the 50/100Hz brum (60/120Hz in USA and other)... more current the load draws-bigger the capacitor needs to be. there is some relationship between the two aforementioned but i'm not sure how it goes so take a peek at google or wiki