In this tutorial, we are going to make a 1.5V - 12V variable 2Amp power supply. Using LM317 Voltage regulator IC.



  1. Output Voltage Range Adjustable From 1.25 V to 37 V
  2.  Output Current Greater Than 2 A
  3. Short-Circuit Current Limiting
  4.  Thermal Overload Protection
  5. Output Safe-Area Compensation


The LM317 device is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5 A over an output voltage range of 1.25 V to 37 V. It requires only two external resistors to set the output voltage. The device features a typical line regulation of 0.01% and typical load regulation of 0.1%. It includes current limiting, thermal overload protection, and safe operating area protection. Overload protection remains functional even if the ADJUST terminal is disconnected. 

Parts Required:

1. LM317

Buy Now

2.  2 X 100uf Capacitor


Buy Now

3. 5K Potentiometer

Buy Now

4. 240 Ohm Resistor.

Buy Now

5. Red Led

Buy Now

6. Crocodile Pin Pair

Buy Now

7. 120 Ohm resistor.

Buy Now

8. Wire And Tools.


  • Now Let's have a look on the IN4001 Diode
  • We will get 12V AC from the transformer now we have to convert that 12V AC to 12V DC by making a Rectifier circuit using 4 IN4001 diodes.
  • Now connect the 4 IN4001 Diode as connected in the diagram below.
  • Now Connect the 12V Ac OutPut of the Transferer to the Rectifier circuit as connected in the Diagram below.
  • Now connect two wires to the other two terminals of the Rectifier circuit.
  • Now connect a 100uF Capacitor to the 12V DC output, Note that please check the VCC and GND of the 12V Dc output from the Rectifier circuit before connecting the capacitor, then connect the +ve terminal of the capacitor to the 12V Vcc and -ve terminal of the Capacitor to the GND of the 12V Dc output.
  •  Now connect Vcc of the 12V DC to the pin 3 of the LM317.
  • Now connect a 240 Ohm resistor in between Pin1 and Pin2 of the LM317.
  • Now Connect the 5k Potentiometer's 1 Pin to the Adjust Pin i.e. Pin1 of the LM317 and another pin of the 5K potentiometer to the GND of the 12V Dc.
  • Now connect one DC On/off switch to the Pin 2 of the LM317 and another pin will provide us the 12V variable Vcc out of our Project.
  • Now connect 120 Ohm resistor to the red led and connect the +ve strand of the led to our 12V Variable Vcc and -ve strand of the Led to the Ground Of our Circuit.So that the Red Led will Glow when we will turn the DC switch on and act as an indicator.
  • Now Enjoy Your 1.5V - 12V variable DC Power supply.

For Making Watch this Video:


Thanks For Watching, Please Like, Share & Comment below for any Query.