It regulates from 5 volts to 50 volts with a high efficiency. It regulates it to around .015A, amplify the .015A it the main transistor, than turn the voltage of with the 100k ohm resistor, than turn the voltage on to the right level(3.3v) with the 86k ohm. When the voltage is high on the output it lowers it more so it is regulated. 3.3 voltage regulators are usually for efficient circuits, why use more than 3.3 volts when it's a constant usage circuits, when the load is not always "ON".
