Solar Cell

However, as the costs of solar cells have fallen and their efficiencies have improved, demand has materialized for large arrays that can power larger facilities or feed into a utility grid ( Fig. 1 ). For residential solar energy systems, PV modules and arrays can be mounted on a structural surface, such as a rooftop and faced toward the Sun ( Fig. 3 ). When powering loads that require ac voltage, a power inverter is used to convert the dc voltage from the solar cell array into usable ac power.