Machine

A/C or alternating current, is the electricity we use in our homes and businesses, D/C or direct current is the electricity from batteries...A/C can be converted to D/C with a rectifier and D/C can be converted to A/C with an inverter.. A/C current differs from D/C in that it reverses the flow of electricity several times a second, in the U.S. 60 times a second, this is called the frequency and is given in hertz(60hz)...This is the most efficient method of transporting current over long distances...You can make machines that run on either a/c or d/c depending on which type of current best suites your needs....but the vast majority of machines are run on A/C...



http://en.wikipedia.org/wiki/Alternating_current
http://en.wikipedia.org/wiki/Direct_current