I am building a simple bi-polar power supply, that will be capable of -/+12VDC at around 1.25A. I have a mains transformer that brings 230VAC down to ~20VAC, with single windings on both sides. And I was wondering, if its possible to generate a +/- voltage from a a single winding on the secondary side, so without the center tap. If it is, what is the best/ most efficent or most used way of doing it?
I would really appreciate if you could provide a schematic.
Would it be better if I used a full-wave rectifier getting only a positive voltage and then using a buck/boost or a similar method to invert it to a negative voltage?
What is the advantage/disadvantage of both approaches?