I have a choice of choosing 1x 9V Duracell battery or 4x AA Duracell batteries. I want to regulate the voltage to 5V with a 7805. From what I understand, the voltage regulators just converts the unwanted energy into heat to reach the regulated voltage.
My best guess for efficiency is using the four AA batteries, less wasted energy and higher mAh. Should I be looking into the drop off voltage for these different power sources?
My application is to power a MCU while data logging without having to change the batteries often. It would be best to have the highest mAh option, but with a maintained voltage.
Is there somewhere I can look to obtain more information on this? Or could I be enlightened?