LM317T Variable Voltage Power Supply

Introduction: LM317T Variable Voltage Power Supply

About: Pursuing B.Sc. in Computer Science from Delhi University at SSCBS.

After searching on internet for a nice power variable power supply based on LM317T voltage regulator i decided to design one of my own. Because i don't find a good pcb design. All the files are uploaded so you can download them. PCB is designed in Eagle Cad.


I used toner transfer method. Soldermask is made by painting the pcb with glass paint.


Parts list:
10uF, 1uF, 2200uF polarized electrolyte capacitor
220ohms, 1k both 1/4 watt resistors
LM317T Voltage regulator and heatsink
3mm led
1N4007, 1N5406 Diodes
Two pin screw terminal

2 People Made This Project!


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14 Discussions


1 year ago

There are 3 caps on the parts list but there are 4 on the actual PCB on the last pic?

What is the output current
What is the output voltage
Can i use volt meter and ampmetar in output
What is the input voltage


2 years ago

4-20 mA current output?
How is how to connect elements?
Please guide me

its not working the 10 k potentiometer goes bom

2 replies

Hello friend. I suggest you to check the wiring again and use a 5k potentiometer instead of 10k. However 10k pot works fine. i have used 10k pot int my construction and it is working great.

Umm , I think there is no ground in the circuit and I have tried the 5k potentiometer and its not working and my transformer is working great and thanks for the reply

perhaps i'm missing something, but what is the input and output voltage and current?

also, it would be nice to have a schematic for those of us who are unable to etch a pcb.

1 reply

The schematic is in the Eagle CAC file (Power Supply.rar). You can open it with the free version of Eagle.

hi Dishendra, nice project... can you please upload the schematic. cheers

Do they have to be pure(I doubt about HCl, though) or not? Sorry for such questions, I have almost no experience whatsoever in electronics. And thanks for replying.