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
Length of a module precisely the simple modules. For every finite-dimensional vector space (viewed as a module over the base field), the length and the dimension coincide. The length of the cyclic group Z/"n"Z (viewed as a module over the integers Z) is equal to the number of prime factors of "n", with multiple prime factors counted multiple times. A module "M" has finite length if and only if it is both Artinian and Noetherian. (cf. Hopkins' theorem) If "M" has finite length and "N" is a submodule of "M", then "N" has finite length as well, and we have length("N") ≤ length("M"). Furthermore,