PHOTOVOLTAIC

The photovoltaic cells for converting sunlight directly into energy electricity, using the so-called "photovoltaic effect", which is based on the properties of certain materials conductors appropriate treatment (including silicon) to directly generate electricity when hit by sunlight.

A photovoltaic cell exposed to radiation Sun behaves like a DC generator with a characteristic curve voltage / current depends basically on the intensity of solar radiation by temperature and the surface. The cell is generally square in shape (but can also be Round or octagonal) with an area of ​​approximately 0.01 square meters and produces, in the irradiation conditions Italian, a current of 3 A (Amps) with a voltage of 0.5 V (volts). The following are the types of solar cells: Monocrystalline cells: are produced by cutting a single crystal bar. The advantage principal and a high efficiency (up to 16%), but are expensive because of the complicated production process. Monocrystalline cells are usually characterized by homogeneous blue coloring. Cell poles (multi-) crystalline: they are cast into blocks and then cut into disks. The yield is minor (10 - 12%), but are cheaper. This type of cells can be recognized by the design produced by the use of different crystals. Amorphous cells: is produced by cathodic deposition of silicon atoms on a plate glass. This type of cell has a lower yield (ca. 4-8%), but also adapts to the case where the incident radiation is not direct but diffused and that in the case of overcast sky. These cells have a dark color and can be made in any geometric shape (circular shapes are possible, octagonal, irregular, and even convex).