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.

A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.

Connecting the 8 batteries in series multiplies their voltage while keeping their current the same yielding a 120V 10A configuration. Connecting the 8 batteries in parallel multiplies their current while keeping their voltage the same yieleding a 15V 80A configuration. Using a series-parallel connection, 4 batteries can be connected in series and 4 can be connected in parallel resulting in a 60V 40A configuration.

Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere.

A transistor works by allowing a small amount of current applied at the base to control general current flow from collector to emitter through the transistor.