Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances. A line drop is a decrease in voltage between two points on an electrical transmission line due to resistance in the line. A lower current and higher voltage across the line will help compensate for the line drop.

Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.

Connecting the 6 batteries in series multiplies their voltage while keeping their current the same yielding a 54V 15A configuration. Connecting the 6 batteries in parallel multiplies their current while keeping their voltage the same yieleding a 9V 90A configuration. Using a series-parallel connection, 3 batteries can be connected in series and 3 can be connected in parallel resulting in a 27V 45A configuration.

An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC.

All electricity is the movement of electrons which are subatomic particles that orbit the nucleus of an atom. Electrons occupy various energy levels called shells and how well an element enables the flow of electrons depends on how many electrons occupy its outer (valence) electron shell.