An electrical contractor in Austin, TX, posted a super-
informative blog post about understanding AC and DC electrical
currents. This is what the differences boil down to: "DC" means
"direct current". DC current moves in one direction. It is
typically used in situations where smaller amounts of power are
required, like in small, battery-operated devices. "AC" means
"alternating current". With alternating current, the current can
move in more than one direction at a time. AC is our standard
electricity in the USA. Since AC current is high power, we need
transformers to transform the electricity from its high-powered
state to a level that is safe to use in our homes.View original
post.