ac power is cheaper and easier to make electronic devices. the power switches for ac power are also less expensive to make. it is less expensive than dc because you can increase and decrease the current very easily. ac can use high voltages with smaller current to reduce losses when you send power. ac reduces the heating in the wires. dc power could be sent, but it would lose a lot of energy and you would have to put more work in it to send it great distances. ac transformers are installed everywhere, including atop utility poles and underground. alternating current works by switching the current many times back and forth constantly while it goes back to the source it came from.