Photovoltic modules use light energy photons from the Sun to generate electricity through the Photovoltic effect Most modules use wafer-based crystalline silicon cells or thin-film cells. The structural load carry member of a module can be either the top layer or the back layer. Cells must 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 Photovoltic junction box is attached to the back of the solar panel and functions as its output interface. External connections for most Photovoltic modules use MC4 connectors to facilitate easy weatherproof connections to the rest of the system. A USB power interface can also be used.
Module electrical connections are made in series circuits to achieve a desired output voltage or in parallel to provide a desired current capability (amperes) of the solar panel or the Photovoltic system. The conducting wires that take the current off the modules are sized according to the ampacity and may contain silver, copper or other non-magnetic conductive transition metals. Bypass diodes may be incorporated or used externally, in case of partial module shading, to maximize the output of module sections still illuminated.
Some special solar Photovoltic modules include concentrates 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 such as gallium arsenide 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.
A solar cell or photo voltaic cell, is an electrical device that converts the energy of light directly into electricity by the photo voltaic effect which is a physical and chemical phenomenon. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light. Individual solar cell devices can be combined to form modules, otherwise known assolar panels.The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 10 to 25 volts