Below is a link to a circuit that I just purchased which accepts AC in and outputs DC. It has an adjustable output as well. The cost is about $2.00 each The size is about 3/4 in by 2 in and is about 7/8 in tall. This should cover most the of questions being asked in this thread.
https://www.ebay.com/itm/AC-DC...p2060353.m2749.l2649
Thanks;
idea-thinker