[Mee-n-Mac]

Originally Posted by Audiofn

The reason that we went with AC is because of the fact that it can be driven much farther then DC as I recall from school.....
{snip}

Yes kinda but with a twist. In an effort to induce 1 more retire... , err ... tuition check from SKip I'll take a cue from mcdude and offer the following history. Back around 1890 or so you could find both AC and DC distribution systems for electrical power. G. Westinghouse (utilizing the genius of wildman Nikola Tesla) was pushing AC and T. Edison (Mr Lightbulb) was promoting DC (at 110 to 240 volts ). Then, as now, nobody wanted a power plant in their backyard and so ideally the plant would be located some distance from the end users. The problem is that wire to carry the electricity impedes it's flow though it (aka resistance) and so you drop voltage, lose power when pushing electrons through the transmission lines from the plant to the house. The power lost in the lines is turned into heat and wasted, unless you're a bird with cold feet. The smaller and/or the longer the wire, the more loss you get. The more current/amperage you flow, the more loss you get. The way around using big fat heavy expensive wires from your remote plant is to use a higher voltage. Power (watts, W) is voltage (volts, V) times current (amps, I) and so for a given power to be transmitted you get less current flow at higher voltages (Wconstant = Vsmall x Ibig = Vhigh x Ismall). Less current flow means less loss through the cables which means more power gets delivered to the customer which is what a power plant operator who gets paid by the watts delivered wants. The advantage was that then, as is true now, you could (can) easily transform 1 AC voltage into another higher or lower AC voltage, with small losses, by using, you got it, a transformer. Thus you can make low to medium voltage at the generator, transform it to a high voltage to send through the transmission lines and then transform it back down to low voltage (like 120 v AC) for the house. This was basically impossible for DC voltage back then and so AC won the day and we have AC now as a result of that competition (which was known as the "War of the Currents"). Of course today we can do DC/DC conversion (just look at any car amp > 50W/channel) but even so it's lossy and "hard" to do compared to AC. So electrical power can be driven further better at high voltages (DC same as AC) but it's AC thats easier, cheaper to make into high and low voltages as needed.

For more than you care to know
http://en.wikipedia.org/wiki/War_of_Currents

ps - Aaah yes all those 10's of thousands of $$ and years of graduate and undergradute electrical engineering schoolin are really paying off now. Yup I can spout off useless boring 'lectrical trivia to no end. Hoo boy can someone please refill my scotch glass ...