Variable Power supply

 

Project by Austin aka ElectroNerdy....

"This is my first attempt at a variable power supply using the LM338 voltage regulator. Apart from the regulator circuit, I also have a separate cell phone adapter that powers my LED voltmeter display. The voltmeter measures in mV so it was necessary to include a voltage divider. Despite the voltage divider, the display still maintains reasonable accuracy. The regulator can provide a range of 1.2V to 29.8V with excellent performance. The output ripple varies between approximately -60dB to -54dB (1mV to 2mV), however, above 29V a saw-tooth wave is evident which has a peak of 50mV. Clearly, the operation is best suited for 1.2V to 29V and no further. I used the regulator design provided in the LM338s datasheet, but I also added several other components as well. I thoroughly enjoyed building this project and I've already used it to power several other projects. I would like to thank everyone who contributed to my success, particularly the host of this site."