DC power supply 3-30V 3-30V 3A stabilized

3-30V power supply 3 A circuit diagramThis DC power supply circuit diagram is designed as an additional or as a permanent power supply for all general circuits based on a stable DC voltage between 3 and 30V provided that current consumption does not exceed 3A. Of course, this DC power supply can also be used to other purposes. By replacing the trimmer by a potentiometer, it can even be used as adjustable supply unit. A good quality heatsink must be used.

DC power supply 3-30V 3-30V/ 3A Specifications:

  • Protection against overloads
  • Short-circuit steady
  • Output current: max. 3A
  • Output ripple voltage: 0.5 mV
  • Output voltage: adjustable from 3 to 30V, stabilized
  • Input voltage: 9 to 30V AC (depending on desired output voltage)

DC power supply 3-30V 3A
Mounting in an enclosure:
Depending on the transformer used, one can choose one of two housings. If a metal enclosure is used, must be connected to safety purposes. Make sure that the heat sink does not touch the housing, this can cause a short circuit.
If the circuit is to be integrated into another unit, the ventilation holes must be provided, which is required to dissipate the heat.

DC power supply 3-30V 3-30V 3A parts List :
R1 = 8.2K
R2 = 2.2K
R3 = 680R
R4 = 1K
R5 = 82K
R6 = 0.18R/5W
C1 = 470p
C2 = 100nF-63V
C3 = 100nF-63V
C4 = 100uF 63V
10KuF C5 =-60V
D1-D6 = 6.6A
Q1 = MJ3001 (Darligton)
IC1 = UA723D


  • Connect a voltmeter to “GND” points and “OUT +” and set “RV1″ until the voltage desired output is reached.
  • Apply some heat-conductive paste to the lower surface of the transistor and mount it on the radiator.
  • If you need 3 to 8 volts then R2 is 5.6K
  • If you need more than 8 volts then the R2 is 2.2K

2 thoughts on “DC power supply 3-30V 3-30V 3A stabilized

  1. Hi there,

    What is the value of “P1″, where is the “RV1″ and what is the “trimmer”?
    Do you have a draw of PCB?

    Thank you.

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