Adjustable Power Supply 3-30V/2.5A

This is an adjustable power supply circuit, also known as variable power supply. . You may use this circuit for general purpose usage.

Here the schematic diagram:
Adjustable Power Supply 3-30V/2.5A circuit 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

Bottom PCB layout:
Adjustable Power Supply 3-30V/2.5A pcb layout

Top PCB layout (Components placement):
Adjustable Power Supply 3-30V/2.5A pcb layout

For complete explanation, circuit's works and how to build this circuit into the box, download the full tutorial here

About Power Supply
A power supply is a device that supplies electrical energy to one or more electric loads. The term of "power supply" is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy (e.g., mechanical, chemical, solar) to electrical energy.
A power supply may be implemented as a discrete, stand-alone device or as an integral device that is hardwired to its load. In the latter case, for example, low voltage DC power supplies are commonly integrated with their loads in devices such as computers and household electronics. More explanation about power supply can be found at

This is the tutorial about "How to build an AC to DC power supply ". The video tutorial covers the basics of diodes, bridge rectifiers, and how to build simple unregulated AC to DC power supplies than can handle a few mA up to several Amps.

Watch the video: