AC stands for Alternating Current. It refers to a current in which movement of electric charge changes direction periodically. In other words, alternating current changes its direction and magnitude periodically, i.e., it starts from 0 grows to maximum, returns to 0 and again grows to the maximum in the opposite direction and then again reaches to original value 0.
This cycle is repeated continuously as long as the AC is flowing in the circuit. Alternating Current is different from direct current (DC) as DC flows only in one direction. The generation and transmission of AC are very easy as compared to DC. So, it is the AC that is used in mains-wired buildings such as homes, offices, factories and other buildings. (Full form of AC)
AC is also used in electric motors that convert electric energy into mechanical energy. Electric motors are present in various electrical appliances like washing machines, refrigerators, etc.