This is Simple 3-30 volt adjustable and stabilized power supply circuit. You can use this circuit for general purpose.
Here the schematic diagram:
Component list:
| R1 = 560R 1/4W | C1 = 100nF |
| R2 = 1,2 K 1/4W | C2 = 2200uF 35-40V |
| R3 = 3,9 K 1/4W | C3 = 100 pF |
| R4 = 15K 1/4W | C4 = 100uF/ 35V |
| R5 = 0,15R 5W | |
| D = B40 C3300/2200, 3A rectifier bridge | |
| P1 = 10K potesiometer | TR1 = BD 135 |
| IC = LM723 | TR2 = 2N3055 |
PCB layout:
Components placement:
For complete explanation, circuit's works and how to build this circuit into the box, download the full tutorial here