5A Adjustable Regulated Power Supply

  • Rajkumar Sharma
  • 27042
  • moderate
  • Tested


This project provides a variable output voltage ranging from 1.2 to 32 V @ 5 A. The project based on LM338K IC. LM338K is an adjustable 3 terminal positive voltage regulator capable of supplying a maximum of 5A over a 1.2V to 32V output range. The circuit is simple and consists of a few components.


  • Input Supply : 24 VAC or 30 VDC, 5 Amp
  • Output : variable output from 1.2 to 32 V @ 5 A regulated low ripple DC voltage
  • Heatsink for regulator IC
  • Onboard bridge rectifier to convert AC to DC
  • LED indication at input of IC
  • Thermal overload/short circuit protection (provided by IC feature)
  • Screw terminal connector for easy input and output connection
  • Berg connector for connecting potentiometer (POT) to the PCB
  • Filter capacitors for low ripple DC output
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 91 mm x 66 mm



Parts List


LM338K Datasheet




  • How about changing the Current like 2 Amp

    4 years ago
    • admin

      You may use a smaller transformer of 2A and have that output as maximum.

      4 years ago
  • JC Droog

    how about current control

    4 years ago
    • admin

      This power supply doesn’t support current control. We are sorry.

      4 years ago
  • mohamed

    in this circiut it needs feedback to make the voltage constant and doesent decrease when adding load at the output how to make this circiut regulated ?????

    3 years ago
    • admin

      Feedback is implemented with R1 and R2, so this is a regulated power supply.

      3 years ago
  • nils

    Hello. I see in list:
    Input Supply : 24 VAC or 30 VDC, 5 Amp
    Does this means the input can be 30DC without your diode bridge or
    24AC with the bridge in circuit
    Thank you

    2 years ago
    • Both of that you describe will work fine.

      2 years ago

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