The sun's light is converted into electricity when it displaces electrons in the semiconductor, photovoltaic material of a solar module. These electrons follow the path of least resistance, which in this case brings them through tiny metallic strips in the module to the junction box on its back. Multiple modules are then wired together in order to construct a system of desired power capacity. The array output is in the form of direct current, and an inverter is required to transform it into alternating current to be grid and appliance compatible. Your PV system's output causes your utility meter to spin backward during the day, allowing the utility to give you credit that can be used during your nighttime demand.