A photoflash battery is a specialized zinc-carbon battery optimized to provide a high electric current output for a very short time, such as required to fire a flashbulb.
Service life for this battery in applications where a lower but continuous current is required, such as for a flashlight with incandescent bulb, is short.
[1] Another common type of photoflash battery is a series assembly of cells, often providing 22.5 volts, used in battery–capacitor flash units.
The battery slowly charges a capacitor, which is then discharged through a flashbulb to provide a high-current pulse to ignite the bulb.
[2] Higher-voltage photoflash batteries were also made to fire reusable xenon electronic flash tubes, which require a high voltage, without the use of circuitry generating this voltage from low-voltage batteries.