BC Flash

BC Flash - Battery-Capacitor Flash. A flash system used with flashbulbs. Instead of relying directly on the current pulse ability of a battery to directly fire a flashbulb (see Photoflash Battery), a battery was used to charge a capacitor, that would then discharge through the flashbulb.

The advantage was that even with an aging battery, the flashbulb would still get a high current pulse and thus reliably fire. As the battery aged, recycle time between flashes would increase, but the flashbulb would still reliably fire. The BC flash units used either 15V or 22 1/2V batteries.

References

Electronics for Photographers, by Marshall Lincoln, Copyright 1966 by Chilton Books, Pages 43 thru 54.

[http://physics.bu.edu/~duffy/PY106/Capacitors.html Capacitors & Batteries]