** - 12V output and GND is reversed(last graphic)**
To build a dual power supply with full wave rectifier circuit, we need a centre tapped power transformer. However we can design a simple dual power with no center tapped power transformer even though efficiency is a little low. 1 ampere guarantied with 7805, 7812, 2824 voltage regulators.
![](https://s2.save4k.ru/pic/D99-z5ZmnzU/maxresdefault.jpg)