Flashlights and Capacitors Why capacitors are used in flashlights of cameras instead of attaching the light directly to the battery? How this leads more light?
 A: There are 3 main reasons for using a capacitor. 
First it stores the energy, so it can deliver a pulse of energy that is far larger than the battery can. Remember it may take several seconds of battery energy to fully charge the flash capacitor. Then the capacitor releases all that in less than a millisecond ($10^{-3}s$) or even just a few microseconds, so the flash bulb gets a massive jolt of energy.
Secondly, the flash capacitor stores the energy at a much higher voltage: we're talking about up to 1000V (typically around 300V), instead of the 6V from 4 AA cells.
Finally, the capacitor is designed so it can deliver extremely high currents, again higher than the battery can deliver by itself.
Finally, the charge can stay on that capacitor for a very long time. Never touch a charged flash capacitor. The energy stored in them can be lethal!
A: Because we don’t need lighting, but flash, that means we have to release much energy is a short time interval. Capacitors could accumulated and release energy fast.
