A photovoltaic array is a linked collection of photovoltaic modules, which are in turn made of multiple interconnected solar cells. By their modularity, they are able to be configured to supply most loads.

The cells convert solar energy into direct current electricity via the photovoltaic effect. The power that one module can produce is seldom enough to meet requirements of a home or a business, so the modules are linked together to form an array. Most PV arrays use an inverter to convert the DC power produced by the modules into alternating current that can plug into the existing infrastructure to power lights, motors, and other loads. The modules in a PV array are usually first connected in series to obtain the desired voltage; the individual strings are then connected in parallel to allow the system to produce more current. Solar arrays are typically measured by the peak electrical power they produce, in watts, kilowatts, or even megawatts.

Costs of production have been reduced in recent years for more widespread use through production and technological advances. One source claims the cost in February 2006 ranged $3-10/watt while a similar size is said to have cost $8-10/watt in February 1996, depending on type. For example, crystal silicon solar cells have largely been replaced by less expensive multicrystalline silicon solar cells, and thin film silicon solar cells have also been developed recently at lower costs of production yet (see Solar cell). Although they are reduced in energy conversion efficiency from single crystalline “siwafers”, they are also much easier to produce at comparably lower cost