Variable DC Power Supply using LM317

Below is the circuit for variable dc power supply

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