Simple transformerless power supply circuits
Learn these transformerless power supply circuits, use a capacitor instead, it smaller and lighter than transformer. There are circuits as follows.
Negative Power Supplies
3 Multi voltage power supply circuits
Multi voltage power supply circuit. There is 2 Dual output, The 12V are +12V,-12V, Ground. And also the 5V are +5V, -5V, Ground. All 1A max.
9V-12V Negative Voltage Regulator using PNP Emitter Follower
See two negative Voltage Regulator circuit ideas. Do you know? we can use PNP transistor and Zener diodes in these example circuit 12V,9V at 700mA output