Project: Build an Adjustable Power Supply Circuit (LM317)

Course Overview:

Photo of the finished version of the LM317 adjustable power supply circuits

In this project, you’ll learn how to convert an old old power supply, such as an old laptop charger, into an adjustable power supply that you can use to power your future circuit experiments.

You’re going to use the LM317, which is a very common and widely available linear voltage regulator.

It can be used to create an output voltage of anywhere from 1.2 to 37 V with 1.5 A of current, depending on the power source. So you could use this circuit to power anything that is battery-powered (1.5 V, 3 V, 3.7 V, 9 V, 12 V), or to power your microcontroller (3.3 V, 5 V).

What You’ll Need

  • 1 x LM317
  • 2 x 1N4007 *
  • 1 x 5 kΩ potentiometer
  • 1 x 240 Ω resistor
  • 1 x 0.1 uF ceramic capacitor
  • 1 x 10 uF electrolytic capacitor
  • 1 x 33 uF electrolytic capacitor
  • 1 x perfboard
  • 2 x screw terminals

* Any diode in the 1N4002-1N4007 series works

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