I find it interesting that while all the electrical wiring in my home is typical AC at home-use voltages, the very first thing that almost everything plugged into it does is concert it to DC. I wonder if it would be feasible/logical/more efficient to have just one AC-to-DC converter per house, and distribute DC throughout the house (in addition to the couple places where things actually want AC), with a different connector and standardized voltage (9V?) and so forth.
It could probably never happen since everything needs to be backwards-compatible for people to use it. It’s just bizarre when I look around me and everything that’s plugged into the wall actually wants DC and needs to convert it first.
Well, the power is going to get converted to a different voltage anyways for each application. Since each device needs to transform its input power anyways, and its not terribly complex to convert AC to DC, one might as well keep the power in the form that maximizes its transportability until the last possible moment.
Good question. I unfortunately do not know enough about voltage conversion techniques to answer it. Are any EEs hanging around this blog?
I have heard a few things about AC vs. DC power.
1) When transmitting power over hundreds of miles, DC is a lot more efficient. I expect the long-distance grid in most places to switch to DC within 50 years. See http://www.economist.com/science/displaystory.cfm?story_id=9539765 .
2) On the other hand, connectors carrying DC current are more prone to corrosion. With AC, any electrochemical changes get canceled out when the current switches direction, but with DC they can build up. I presume this issue can be designed around, so I doubt this is a show-stopper for DC.