This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall transformers with variable output voltage are available from any ...

This design was conceived as an add-on for the Variable DC Power Supply, a very successful circuit posted to this website. This simple unit provides a dual-rail variable output ranging from ±2.5V to ...

For an upcoming road trip, [Patrick] needed a small variable power supply. Instead of lugging around a bench supply, [Patrick] did the sensible thing and reverse engineered a cell phone charger to fit ...