LM317 Variable Power Supply: Build Your Own Circuit

Adhere to all necessary safety protocols when working with alternating current. Ensure proper insulation of connections on the transformer.

Circuit diagram

Description:

This particular circuit represents a remarkably enduring design. The LM317 is a remarkably adaptable and efficient 1.2-37V adjustable voltage regulator, capable of delivering up to 1.5A of current with an appropriate heat sink. It’s perfectly suited for a wide range of applications. It was my initial construction for a portable workbench power supply and continues to be a valuable tool. The LM317 incorporates built-in protection against short circuits, rendering a fuse superfluous. Automatic thermal shutdown ensures operation ceases automatically if overheating occurs. This represents a comprehensive and economical package, effectively. Despite the LM317’s capacity to produce up to 37V, the presented circuit is constrained to 25V to prioritize safety and straightforward implementation. Elevated output voltages would necessitate supplementary components and a larger heat sink. Maintaining an input voltage at least a few Volts above the desired output is advisable. A trimmer potentiometer can be utilized when constructing a stable, fixed-voltage supply.

Possible uses:

Adjustable workbench power supply, fixed-voltage supply… Virtually any conceivable application is possible as long as a current draw of no more than 1.5A is required.