A photoflash battery is a specialized zinc-carbon battery optimized to provide a high

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...

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 A flashlight ( US, Canada) or torch ( UK, Australia) is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the ...

with

incandescent bulb An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxida ...

, is short. Photoflash

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

were in production during the flashbulb era, and were phased out as

alkaline cell An alkaline battery (IEC code: L) is a type of primary battery where the electrolyte (most commonly potassium hydroxide) has a pH value above 7. Typically these batteries derive energy from the reaction between zinc metal and manganese dioxi ...

s came into general use, and one-use flashbulbs were replaced by

electronic flash A flash is a device used in photography that produces a brief burst of light (typically lasting 1/1000 to 1/200 of a second) at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a ...

. The photoflash cell was produced in 1.5 volt D, C, and AA size. The

cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...

of a zinc-carbon cell is usually made of powdered carbon black (or

acetylene black Polyacetylene (IUPAC name: polyethyne) usually refers to an organic polymer with the repeating unit . The name refers to its conceptual construction from polymerization of acetylene to give a chain with repeating olefin groups. This compound is ...

manganese dioxide Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...

and

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...

. The MnO₂ to carbon ratio varies between 10:1 and 3:1 for general purpose cells, but a 1:1 mixture is used for photoflash batteries, allowing a high current output with intermittent use, as required for photoflash use. These cells have lower capacity than those with a higher content of MnO₂.David Linden, Thomas B. Reddy (ed). ''Handbook Of Batteries'', 3rd Edition. McGraw-Hill, New York, 2002 Chapter 8. Another common type of photoflash battery is a series assembly of cells, often providing 22.5 volts, used in

battery–capacitor flash A battery–capacitor flash (BC flash) is a flash photography system used with flashbulbs. Instead of relying directly on the current pulse ability of a photoflash battery to directly fire a flashbulb, a battery is used to charge a capacitor ...

units. The battery slowly charges a capacitor, which is then discharged through a flashbulb to provide a high-current pulse to ignite the bulb. 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. Eveready battery manufactured the 240-volt Eveready 491 (NEDA 729) battery, and the 497 battery providing 510 volts and 180 volts.

References

External links

Cell Construction - Information on MnO2 ratios
Battery types {{tool-stub

See also

References

External links