Ah the venerable 7805, who amongst us has not used this popular linear regulator? This big chunky regulator will help you get your 7-35V battery or wall adapter down to a nice clean 5.0V with 2% regulation. Perfect for just about all electronics!  This is the TO-220 version, with up to 1.5A current capability, and has internal current limiting + thermal shut-down protection which makes it sturdy and pretty much indestructible - at least...

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...

Need a nice little 3.3V regulator? We rather like the very-low-dropout L4931 from ST! This little guy will help you get your 4-20V battery or wall adapter down to a nice clean 3.3V with 2% regulation. Perfect for just about all electronics!  This is a TO-92 package version, with up to 250mA current capability, and has internal current limiting + thermal shut-down protection which makes it sturdy and pretty much indestructible - at least...

Need a nice little 5V regulator? We rather like the very-low-dropout L4931 from ST! This little guy will help you get your 5.5-20V battery or wall adapter down to a nice clean 5V with 2% regulation. Perfect for just about all electronics!  This is a TO-92 package version, with up to 300mA current capability, and has internal current limiting + thermal shut-down protection which makes it sturdy and pretty much indestructible - at least...

A voltage detector is handy for projects where you want to make sure your microcontroller doesn't run at a low voltage. For example, say you have a Feather Huzzah running on a lipoly battery every few minutes. Eventually the battery runs down, and goes below 3.3V, so the voltage to the ESP8266 core is too low, and could cause a lockup or corrupted data. Or maybe your battery is already drained and you're trying to charge it back up, but...