Characteristics of a cell: IV curve

To obtain them, it is sufficient to connect a load (resistance) and make its value vary from zero to infinite. By measuring the current I and the voltage V, the curve I(V) is obtained for a defined temperature and solar irradiance.
Voc [V]: Open circuit voltage, when the charge is infinite.
Isc [A]: Short circuit current, when the charge is zero. Such as the power is given from the current multiplied by the tension, the curve P(V) is also obtained by the power in function when the charge varies from zero to infinite.
Current-tension curve I(V): As it can be observed, for a constant temperature and solar irradiance, a value of tension (and thus of charge) exists where the cell supplies maximum power. At this point, the MMP (Maximum Power Point), meaning the yield of the cell is at its maximum.

Conversion yield

Correlation between the supplied power for a PV element and the received solar power. For example, if a square cell of 0.1m side length receives a 1000W/m2 solar irradiance and supplies a 1.2W electrical power, its conversion yield is: 1.2W / (1000W/m2 x 0.01m2) = 12%. It is important to distinguish the intrinsic conversion yield of the cells used and the one of the PV modules (that depends on the relation between the active surface and the total surface).

Crystalline solar cell

Ii is the most widespread photovoltaic technology (approximately 93% of the market). The cell is the fundamental element of the photovoltaic generation and is consisted of a "wafer" (thin silicon block). Silicon, the semiconductor material that converts the solar radiation in electric energy, can be monocrystalline or multicrystalline.