There are two different ways that electricity is produced. The first, and the simpler type, is called direct current (abbreviated "DC"). It is the type of current you get from batteries, static, and lightning. If an electrical charge (voltage) is created or stored in a closed circuit, it causes electrical energy to flow in one direction through the closed loop similar to water flowing in one direction through a closed loop of pipe.
The other type of electricity is called alternating current, or "AC". This is the type of electricity that comes from the wall sockets throughout your house to power most of your electrical appliances. Unlike DC that flows in only one direction, alternating current, as well as the voltage that produces it, cycles back and forth in the circuit very rapidly. Each time the current alternates from one direction to the other and back again it completes one cycle. In most of North America, this occurs 50 to 60 times per second and this type of service is referred to as 50/60 cycles AC.
To change DC to AC requires a device called an “Inverter.”