Photovoltaic system and is typically less useful than a calculation of return on investment. While it is typically calculated to be between 10 and 20 years, the financial payback period can be far shorter with incentives. Due to the low voltage of an individual solar cell (typically ca. 0.5V), several cells are wired "(also see copper used in PV systems)" in series in the manufacture of a "laminate". The laminate is assembled into a protective weatherproof enclosure, thus making a photovoltaic module or solar panel. Modules may then be strung together into a photovoltaic array. In 2012, solar panels available for consumers
Injective module number of results are known, . Let "S" and "R" be rings, and "P" be a left-"R", right-"S" bimodule that is flat as a left-"R" module. For any injective right "S"-module "M", the set of module homomorphisms Hom( "P", "M" ) is an injective right "R"-module. For instance, if "R" is a subring of "S" such that "S" is a flat "R"-module, then every injective "S"-module is an injective "R"-module. In particular, if "R" is an integral domain and "S" its field of fractions, then every vector space over "S" is an injective "R"-module. Similarly, every injective "R"["x"]-module is an