Circuit Lake

Electronic Project and Circuit Collection

Adjustable 1.5 – 35 Volt DC Regulated Power Supply

05/12/2012 Category: Analog, Power Supply, Project

This small power supply provides a regulated voltage, adjustable between 1.5V – 35V at 1 ampere. This circuit is built based on IC LM317. This circuit is ready to use, you just need to add a suitable transformer. This circuit is thermal overload protected because the current limiter and thermal overload protection are included in the IC.

This power supply is good solution to power your projects and save money on batteries. You can also use it for control DC motors and low voltage light bulbs experiments. It has not to be cooled if used for small powers. 28 Volt AC max is allowed for the input voltage.

DIY DC power supply, 1.5-35V

Power Supply Circuit Diagram

Variable 1.5-35V DC power supply

Transformer Selection Chart for Power Supply

Transformer Selection table for Power Supply


  • 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 heat sink)
  • Dimensions: 52x52mm (2.1″ x 2.1″)

Technical Specifications

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