I have a very limited knowledge of electrical engineering that almost entirely revolves around music equipment. From everything that I’ve seen, music equipment ends up converting the AC power to DC power right at the power entry point (or at least soon after). It appears they’re converting AC power to a higher voltage and current DC power. Is the only real advantage of AC power to pump more power over a line to where devices will then manipulate it to what they need in DC? Are there any common household items that actually fully operate off of AC power or does everything convert to DC at some point?
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As people have said (roughly): you can induce voltage into a wire by moving a wire through a magnetic field. (the wire must be “cutting” magnetic flux lines). Constant current creates a steady magnetic field so voltage in a transformer, for example, is only induced when power is turned on or off (this is how the coil to power the spark plugs in a car work). Since ac power is constantly changing current its magnetic field is constantly building and collapsung and thus the magnetic field lines are constantly crossing the wires in a transformer. Since you need really high voltage to transmit power efficienciently (or even to be possible for long distances) and much lower voltages to not electrocute anything within a few feet of an outlet, you need to have an easy way to change voltage efficiently, something only really possible with transformers and thus ac power. Furthermore, on the most basic level, every rotating style generator (so only excluding things like solar or batteries) creates ac power. (yes there are dc generators but they use diode packs to rectify ac into DC) finally, as people said, big (ish) motors, many lights, stoves, pretty much any heater, etc use ac directly. Last point of clarification: as power is not any more easily transmissible than DC for the same voltage/current, ac simply lends itself to easily changing voltage. Also, it is easy to convert ac to DC (I could build a rectifier with 6 diodes and ideally a capacitor super easily), but pretty hard actually to convert DC to ac with any efficiency.
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