Solar power modules use light energy (photons) from the Sun to generate electricity through the photovoltaic effect. Most modules use wafer-based crystalline silicon cells or thin film cells. The loads carrying member of a module can be either the top layer or the back layer. Cells are required to be protected from mechanical damage and moisture. Most modules are rigid, but semi-flexible ones based on thin-film cells are also available. The cells are connected electrically in series, one to another to a desired voltage, and then in parallel to increase amperage. The wattage of the module is the mathematical product of the voltage and the amperage of the module.
A Photo-Voltaic (PV) junction box is attached to the back of the solar panel and functions as its output interface. External connections for most photovoltaic modules use appropriate connectors to facilitate easy weatherproof connections to the rest of the system.
Module electrical connections are made as per design to achieve a desired output voltage in series or in parallel to provide a desired current capability (amperes) of the solar panel or the PV system. The conducting wires that take the current off the modules are sized according to the current carrying capacity and may contain silver, copper or other non-magnetic conductive transition metals. To meet the site condition requirements; diodes may be incorporated or used externally, to maximize the output of module.
Some special solar PV modules are provided with concentrators in which light is focused by lenses or mirrors onto smaller cells. This enables the use of cells with a high cost per unit area (the technology is still evolving and at rapid pace) in a cost-effective way.
Solar panels also use metal frames consisting of racking components, brackets, reflector shapes, and troughs to better support the panel structure.