Ah the esteemed LD1117, who amongst us has not used this popular low drop voltage regulator? This big chunky regulator will help you get your 4-15V battery or wall adapter down to a nice clean 3.3V with 1% regulation. Perfect for just about all electronics!  This is the TO-220 version, with up to 800mA current capability, and has internal current limiting thermal shut-down protection which makes it sturdy and pretty much indestructible - at least electronics-wise (we're pretty sure a hammer might work...)

This regulator has a ~1V linear drop-out, better than the 780X series' 2V. That means you must give it at least 4.3V to get a clean 3.3V out. This regulator is often used to get a 5V power supply to a a clean 3.3V. There is a constant 'quiescent' current draw of 5mA.

This regulator can provide up to 800 mA as long as it has proper heat-sinking. The higher your input voltage and output current, the more heat it will generate. Without an extra heatsink, you can burn off up to 2W.   It's a TO-220 package, so use 62.5°C/Watt junction thermal resistance. The wattage of your set up is = (InputVoltage - 3.3V) * AverageCurrentInAmps. E.g. a 9V power plug and 0.5 Amp of average output current means the regulator is burning off (9 - 3.3)*0.5 = 2.85 Watts!  Or you could use a 5V power supply for (5-3.3)*0.5 = 0.85W which would not require a heatsink.

This regulator requires