Connecting the 6 batteries in series multiplies their voltage while keeping their current the same yielding a 90V 10A configuration. Connecting the 6 batteries in parallel multiplies their current while keeping their voltage the same yieleding a 15V 60A configuration. Using a series-parallel connection, 3 batteries can be connected in series and 3 can be connected in parallel resulting in a 45V 30A configuration.

Circuits are not limited to only series or only parallel configurations. Most circuits contain a mix of series and parallel segments. A good example is a household circuit breaker. Electrical outlets in each section of the house are wired in parallel with the circuit breaker for that section wired in series making it easy to cut off electricity to the parallel parts of the circuit when needed.

Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.

Current is the rate of flow of electrons per unit time and is measured in amperes (A). An ammeter is used to measure the electric current in a circuit.

In the NM cable used for wiring homes, each cable has three wires inside a sheath with each wire covered in a different color of insulation to indicate its type. The wire with the black insulation is the 'hot' wire, white is the neutral wire, and the ground wire is either covered in green insulation or left bare.