C

The C battery follows the same IEC 60086-2 alkaline standard as AA and AAA, using the LR14 code, but it has become far less common in modern consumer electronics. Through the mid-20th century, C cells powered mid-size flashlights, portable radios, and toys that needed more sustained current than an AA could comfortably deliver, trading portability for a much larger internal volume and capacity.

As devices have grown more power-efficient and rechargeable lithium-ion packs have taken over higher-drain applications, the C cell's niche has narrowed mostly to battery-powered lanterns, some medical equipment, and large flashlights where its higher sustained-current capability still matters more than size.

A C cell and an AA cell can both be alkaline at the same 1.5V nominal voltage, so the functional difference is capacity and how well each holds up under sustained heavy current draw -- larger cells generally lose proportionally less of their capacity at high discharge rates than smaller ones. That's why devices drawing continuous high current, like larger flashlights or bullhorns, specify C or D cells rather than AA: the extra internal volume translates directly into longer run time under load, not a different voltage or chemistry.