AA battery
The AA battery (or double-A battery) is a standard size single cell cylindrical dry battery. ANSI and IEC battery nomenclature gives several designations for cells in this size, depending on cell features and chemistry. The IEC 60086 system calls the size R6, and ANSI C18 calls it 15. It is named UM-3 by JIS of Japan. Historically, it is known as D14 (hearing aid battery), U12 – later U7 (standard cell), or HP7 (for zinc chloride 'high power' version) in official documentation in the United Kingdom, or a pen cell.
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.