Hello!
I’m in the process of developing one of my many whiz-bang ideas, and it devolves around the ESP8266 family of devices. (The Adafruit family have screened themselves out.) Now the question:
“Can the SparkFun ESP8266 Thing - Dev Board (with headers) be powered from its headers?”
It’s a case of not being ready to solder on the power connection spots, so I’m wondering if the pair marked 3.3v and ground are output of 3.3v and return to ground? Or are 3.3v input and with ground performing the usual function?
Yep, use the VUSB to supply up to 6v ESP32 Thing Hookup Guide - SparkFun Learn (scroll to the ‘powering’ section). You can also use the 3.3v pins to power, but it needs to be regulated and be between 2.2 and 3.6v per the notes
Check out the schematic and you can see that vbat has its own circuit that ties into vusb and that then goes to the voltage regulator (ap2112k) and get down-regulated to 3.3v