Introduction: Variable Bench Power Supply From Scratch Using Laptop Adapter & LM317

In this tutorial i will show you how to build a Simple & Easy Variable Bench Power Supply from scratch using laptop adapter & LM317.

To build your own Variable Bench Power Supply you can watch the video embedded in this step or continue reading

Step 1: Parts List

Picture of Parts List

***Parts List***

1. LM317

2. Digital Voltmeter

3. 4.7K Pot & Pot Knob

4. Capacitor (0.1uF ceramic & 10uF/50v Electrolytic)

5. Resistor(120 Ohms)

6. Heat Sink

7. Strong Glue

8. Cardboard

9. 2 & 3 Terminal Blocks

10. DC Jack

11. Laptop Adapter with female plug (optional, you can use any adapter which has rating under 40 Volt)

12. 1N4001 - 2


***Purchase or Affiliate Link***

1. LM317 -

2. Digital Voltmeter -

3. Heat Sink -

4. Pot Knob -


1. LM317 -

2. Digital Voltmeter -

3. Heat Sink -

4. Pot Knob -

Amazon USA

1. LM317 -

2. Digital Voltmeter -

3. Heat Sink -

4 .Pot Knob -

Amazon IND

1. LM317 -

2. Digital Voltmeter -

3. Heat Sink -

Note: all the purchase links provided are affiliate links

Step 2: Circuit & Block Diagram

Picture of Circuit & Block Diagram

Construct the LM317 circuit as shown in the circuit diagram. Once the circuit is completed, make a box which can hold your circuit & other components.

Once the box has been constructed follow the block diagram & connect circuit to the Display, Output & the Input.

Features of this Power Supply

1. Max input voltage - 40 Volt

2. Short Circuit Protection

3. 3 Digit voltage Reading

4. Can adjust voltage from 3.5 to 35 volt using pot (the output is dependent on the input)

For the step by step construction you can watch the video by Clicking Here


About This Instructable




Bio: I like making new things from trash. For more cool content please subscribe to my YouTube channel @
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