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ELI5: Capacitors

Electronics are becoming ever more prevalent in my uni course (I'm doing sound engineering). Knowing how your own equipment works and stuff is integral but what is a capacitor. I failed physics in school almost. What does it do. Help.
gpt
Basically a capacitor stores an electrical charge. However unlike a typical battery, which stores electric charge through a chemical reaction, a capacitor stores its charge as a build up of static charge. The exact same kind of static charge you get from rubbing a balloon on your hair, or rubbing your socks on a carpet. A capacitor can build or release its energy really fast, but it doesn’t last very long. This is perfect for a lot of applications. An easy example is the flash bulb on a camera. The bulb is powered by a capacitor that can dump all of its energy in a fraction of a second. You couldn’t get that fast of a release out of a chemical battery. With old camera you can sometimes hear a high pitched whine as the capacitor recharges after a flash. Big electric motors also use capacitors to help kick-start themselves. 

Capacitors are also really useful in tons of other electronics because they act like a little reservoir. In converting AC to DC, capacitors help to smooth out the flow of electricity between the ups and down of the AC current.  They are also all over audio equipment, both in power delivery and signal processing.