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
G-module G-module In mathematics, given a group "G", a "G"-module is an abelian group "M" on which "G" acts compatibly with the abelian group structure on "M". This widely applicable notion generalizes that of a representation of "G". Group (co)homology provides an important set of tools for studying general "G"-modules. The term "G"-module is also used for the more general notion of an "R"-module on which "G" acts linearly (i.e. as a group of "R"-module automorphisms). Let "G" be a group. A left "G"-module consists of an abelian group "M" together with a left group action ρ : "G"×"M" → "M"