Variable output Voltage regulator

using LM317 IC

This is part of the starter blog for IC Basics. Check out here for all of them.

A voltage regulator is often used to get the required voltage supply for projects and circuits. The problem with fixed power supplies is that you need different regulators for different outputs (that is a headache!). So here we will make a variable voltage regulator using the LM317 IC. The LM317 looks like this :

What you need

You will need the following parts.

  1. LM317 – 1pc
  2. 10kΩ variable resistor – 1pc
  3. 240Ω resistor – 1pc
  4. 10 uF capactor – 2pc

Following is a pic of all the parts

What to do

Wire the following circuit on the breadboard. The two capacitors are used to prevent spikes.

Vary the variable resistor. This will give an output varying between 1.25 volts to the input voltage you supply (must be less than 37 volts). Here we are giving a 9v input, so the output will range between 1.25 to 9 volts. Enjoy!

Check out the following if you are done with this one.

Feel free to ask any queries in the comment section below.


Variable output Voltage regulator using LM317 IC

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