Variable DC Power Supply using LM317

Variable 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
 

Regulated DC Power Supply Circuit

Below is the regulated DC power supply( 12, 8, 5 v) circuit. This circuit can be customized by adding 9v and 6v voltage regulator.

Also, the 4 diodes can be replaced by bridge rectifier.



If you are looking for a variable power supply then click here

Basic Power Supply Circuits - Part 2

Simplest DC power supply circuit using 78XX is shown below.



Parts

D1, D2, D3, D4 - 1N4007

IC1 - 7812

IC2 - 7805

C1 – 1000 mf

C2 – 330 mf

C3 – 10 mf

T1 - 12 v Step down transformer, 1 A.