Hey guys ... I have inserted a picture of the question as it was easier to scan than to re-write :P It's based on Switching Mode Power Supplies. 1. The problem statement, all variables and given/known data Check the picture or the upload on photobucket here ... It is basically a full bridge config that is required. What got me was that the supply ranges from 220Vac down to 12Vdc BUT the o/p is 12Vdc ... I got a bit confused as to what config to use. 2. Relevant equations All equations are to be derived from first principles as such. 3. The attempt at a solution Heres the 3 links first .... (1) (2) (3) I kinda need someone to at least just check the work .. coz it is worth a lot of marks (25 out of a 100 mark paper) and I really need to know if my method is indeed right! Thanks so much!