1.2 to 35 Volt DC Regulated Power Supply

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Overview

In today’s tutorial, we are going to make a “DC Regulated Power Supply Circuit” using LM317 IC.

This 1.5 to 35 Volt DC Regulated Power Supply Circuit unveils a compact power supply designed to deliver a regulated voltage, with adjustability ranging from 1.5 to 35 volts at 1 ampere. Ideal for various applications, this ready-to-use circuit merely requires the integration of a compatible transformer. Notably, the circuit incorporates thermal overload protection, courtesy of the included current limiter and thermal overload protection features within the integrated circuit (IC). This ensures the reliability and safety of the power supply under diverse operating conditions.

DC Regulated Power Supply

A DC-regulated power supply is an electronic device that provides a stable and constant direct current (DC) voltage output, regardless of variations in the input voltage or changes in the load.

Hardware Components

To make a regulated Power Supply, you’ll need the following hardware components to get started:

S.noComponentsValueQty
1Integrated Circuit ICLM3171
2Polar CapacitorsC1 = 100nF – 63V
C2 = 1uF – 35V
C3 = 10uF – 35V
C4 = 2200uF – 35V
1
1
1
1
3DiodesD1-D4 = 1N40074
4ResistorsR1 1201
5PotentiometerP1 = 4.7K1

Schematic

Transformer Selection Chart:

Max DC Output VoltageTransformer Rating
3 – 5V9VAC / 15VA
5 – 8V12VAC / 30VA
8 – 13V15VAC / 30VA
13 – 15V18VAC / 30VA
15 – 18V22VAC / 30VA
18 – 22V24VAC / 50VA
22 – 35V28VAC / 50VA

Specifications

  • Preset any voltage between 1.5 and 35V
  • Very low ripple (80dB rejection)
  • Short-circuit, thermal, and overload protection
  • Max input voltage: 28VAC or 40VDC
  • Max dissipation: 15W (with heatsink)

Technical Specifications

  • Input Voltage = 40Vdc max Transformer
  • Output Voltage = 1.5V to 35Vdc
  • Output Current = 1.5 Amps max.
  • Power Dissipation = 15W max (cooled)

Note: It has not to be cooled if used for small powers. 28 Volt AC max is allowed for the input voltage.

Applications

  • Great to power your projects and save money on batteries
  • Suitable as an adjustable power supply for experiments
  • Control DC motors, low voltage light bulbs, etc

Conclusion

This DC Regulated Power Supply Circuit offers a reliable and adjustable solution for powering electronic circuits. With its user-friendly design and thermal overload protection features, this compact power supply stands ready for diverse applications.