In my high school physics class, we've been talking a lot about circuits of late. And, in such a discussion who can forget capacitors?
Most people know that capacitors are usually created by separating to conducting plates by a small dielectric. They store electrical charges and in doing so store electrical energy through a temporary electric field. That's all fine and good, but where is this invention used in the real world and for what purpose?
Well, one basic use is the storage of energy. Some devices are much easier to use if they can keep charged while their battery is replaced or fixed. Usually this appears when devices need to keep their memory files when no longer connected to a power source. Or, capacitors can be used to make UPS's, or Uninterruptible Power Supplies. These devices maintain voltage to a device when the normal electricity source is obstructed, usually so that nothing is lost or damaged before a backup generator turns on.
Capacitors can also be used to smooth out DC currents. This can include signals traveling to audio devices, in which the capacitor resists any extra electrical power. They can even separate AC and DC currents, since AC passes through unchanged while DC current is absorbed to charge the capacitor.
They are also often used to start up motors. Since starting an electrical motor is always much harder than running one, sometimes capacitors can be used to deliver a kick start. This can often be seen in hair dryers and vacuum cleaners.
There are plenty of uses for your friendly neighborhood capacitor! Thank Farad they were invented and perfected over the years!
--Notice: do NOT mess with capacitors. Because they release large amounts of charge in small amounts of time they are VERY DANGEROUS. Vacuum cleaners often feature capacitors which are more than large enough to kill a human being. Stay away and respect the power of electricity--