[Ladyada] is working on a tutorial series covering power supplies. If you’ve ever built an electronic project you’ve used some type of power supply but we think that most people have no… ...

Oftentimes the biggest obstacle indesigning an isolated dc/dc converteris the transformer design, a prospectthat sometimes discourages designersfrom undertaking an otherwisestraightforward design task ...

Principles of converter circuit analysis are introduced and are developed for finding the steady-state voltages, current, and efficiency of power converters. Assignments include simulation of a dc-dc ...

So, power supply guru suspects DC leaking back from the rectifier causing transformer to hum. Solution is a a capacitor between transformer and wall.

Linear Technology's LTM2881 µModule RS-485/422 transceivers provide inductive isolation and incorporate a dc-dc power supply, including the transformer.