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 formal algebraic geometry. Let "M" be a (left or right) module over some ring "R". Given a chain of submodules of "M" of the form we say that "n" is the "length" of the chain. The length of "M" is defined to be the largest length of any of its chains. If no such largest length exists, we say that "M" has infinite length. A ring "R" is said to have finite length as a ring if it has finite length as left "R" module. The zero module is the only one with length 0. Modules with length 1 are