Variable DC Power Supply using LM317

Below is the circuit for variable dc power supply

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R1- 240 Ω

R2- 5K VR

R2 can be replaced by fixed value resistor for fixed power supply. Following formula can be used to calculate output voltage.

Vo=1.25(1+R2/R1)

Output voltage should be2 voltage greater than input.

Parts for current setup

  •  D1, D2 – 1N4001
  • C1-0.1 μ
  • C2 – 10 μ 50v
  • voltage regulator – LM317

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