This project details the design of a very low dropout adjustable power supply. A good power supply is essential to electronic projects, and being able to hook this up to a breadboard makes it very useful to hobbyists. It features a dropout of only 40mV – 400mV compared to 1.25V – 2.0V for a LM317 circuit. This means you can use a wider range of input/output voltages, including generating 3.3V from as low as 3.7V (such as 3 AA’s or a lithium ion battery)!
Low Dropout Adjustable Breadboard Power Supply – [Link]