Nine-volt battery

Uncommon card · No. 189619

The nine-volt battery, or 9-volt battery, is an electric battery that supplies a nominal voltage of 9 volts. Actual voltage measures 7.2 to 9.6 volts, depending on battery chemistry. Batteries of various sizes and capacities are manufactured; a very common size is known as PP3 (IEC alkaline 6LR61), introduced for early transistor radios. The PP3 has a cuboid shape with rounded edges and two polarized snap connectors on the top. This type is commonly used for many applications including household uses such as smoke detectors, gas detectors, clocks, and toys. The nine-volt PP3-size battery is commonly available in primary zinc–carbon and alkaline chemistry, in primary lithium iron disulfide and lithium manganese dioxide (sometimes designated CRV9), and in rechargeable form in nickel–cadmium (Ni–Cd), nickel–metal hydride (Ni–MH) and lithium-ion. Mercury batteries of this format, once common, have been banned in many countries due to their toxicity. Designations for this format include NEDA...

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