stupid question here: I read a lot, that the esp8266 can handle 5V as input. So i bought an battery pack, which can handle 3 AAA-batteries and wired this to a micro usb plug. But now, i read that those devices can only handle 3.3V. I also have the new esp32 thing here and with this, i have the same question.
How much voltage is minimum and how much is the maximum? Are 3.3V enough, when i only want to wire an sd card adapter on my esp32 which needs 3.3V?