9volt

9volt commonly refers to the standard 9-volt battery, a rectangular primary battery used in a variety of small electronic devices. In official terms, it is often designated as a PP3 size battery in the IEC system and is frequently colloquially called a 9V battery.

The typical 9-volt battery is formed by six small single cells connected in series to produce approximately 9 volts when fresh. The most common chemistries are alkaline and lithium primary cells, with alkaline versions being the most widespread for consumer devices. Rechargeable variants exist, primarily nickel–metal hydride (NiMH) types, but they are less common and may require specific devices or chargers. The rectangular shape features snap connectors on the top surface, with positive and negative terminals arranged to interface with device contacts.

Usage and performance vary by chemistry and load. Alkaline 9-volt batteries offer modest energy capacity and voltage tends to sag under heavier current draw, which makes them less suitable for high-drain applications. They are widely used in devices such as smoke detectors, wireless microphones, clocks, handheld meters, and some guitar effects pedals. Rechargeable 9-volt batteries can reduce waste and long-term cost in devices with frequent replacement, but they may have lower capacity or different discharge characteristics and may not be compatible with all devices.

Safety and disposal considerations include avoiding short circuits, puncturing, or exposing batteries to high heat, which can cause leakage or rupture. Used 9-volt batteries should be recycled or disposed of according to local regulations. While a convenient power source for small devices, the 9-volt battery is often challenged by modern devices that favor smaller or rechargeable pack configurations.