This [site](https://www.batterypowerzone.co.za/blog/60/why-are-batteries-called-aa-and-aaa) breaks it down.
AAA batteries are smaller compared to A. The smallest battery is of pin-shaped, 3.5mm diameter lithium-ion.
AAA batteries carry a smaller amount of mixture as compared to the AA.
AAA batteries carry a smaller amount of charge as compared to the AA.
AAA batteries are used in low power (small) devices, while AA batteries are used in high power (small) devices.
Your cylindrical alkaline batteries all have the same voltage. AAA, AA, C, D are all 1.5 V. They have the ability to satisfy higher current (draw) the larger they get. If you could adapt a C battery to a device requiring a D cell, it would still run but it might not run for very long. Small devices typically don’t require much current, so the battery can be made smaller, allowing for a reduction in size of the device.
Latest Answers