Connecting the 4 batteries in series multiplies their voltage while keeping their current the same yielding a 60V 5A configuration. Connecting the 4 batteries in parallel multiplies their current while keeping their voltage the same yieleding a 15V 20A configuration. Using a series-parallel connection, 2 batteries can be connected in series and 2 can be connected in parallel resulting in a 30V 10A configuration.

Resistance is opposition to the flow of current and is measured in ohms (Ω). An ohmmeter is used to measure the amount of resistance at a certain point in a circuit.

A semiconductor is a material that has a limited ability to conduct electrical current with conductivity between that of an insulator and that of a conductor. Silicon, a cheap and abundant material, is the most used semiconductor material although other materials are used in the electronics components made from semiconductors. The primary advantages of a semiconductor over a conductor is that the conductivity of a semiconductor can be varied under an external electrical field giving engineers precise control over complex circuits and, unlike conductors like metals, a semiconductor's conductivity increases with increased temperatures.

The hertz is a unit of measurement for frequency.

An electrical circuit is a path through which electricity flows. This path contains one or more components that create a load (something that is using electricity) and that load acts as resistance to the passage of electricity through the circuit. Electricity can only flow through a circuit when the path is closed and cannot flow through an open circuit.