The AA battery (or double-A battery) is a standard size single-cell cylindrical dry battery. AA batteries are common in portable electronic devices. An AA battery is composed of a single electrochemical cell that may be either a primary battery (disposable) or a rechargeable battery. Several different chemistries are used in their construction. The exact terminal voltage, capacity, and practical discharge rates depend on cell chemistry; however, devices designed for AA cells will usually only take 1.2-1.5 V unless specified by the manufacturer. ［Wiki］
 

AA battery typically used in small electronic devices, which is also a battery with a standard length of 51 mm and a diameter of approximately 14 mm. AA and AAA are battery designations that are used to indicate the size and potential charging capacity of certain batteries. The most notable difference between the two is their size. AAA batteries are smaller than AA batteries. AA batteries are best for low power drain devices such as camera flashes because they last much longer than AAA batteries. By contrast, AAA batteries are the better choice for high-power battery devices such as video game controllers because they provide a more current and higher voltage.


How many volts is a AA battery?

AA battery starts off with 1.5 volts of energy, but they’ll gradually lose their voltage throughout their use, reducing the device’s performance over time.

Is a 1.5 V Battery the Same as AA? 

A 1.5-volt battery is the same size as AA batteries, but is rated for lower voltage to suit a device with a lighter power requirement such as a flashlight. Mixing them together will result in low-voltage operation of electronic devices.