One individual silicon solar cells provides under nominal conditions, on average, in the order of 600 mV and 30 mA/cm2. Solar cells are then rarely used individually. Rather, cells with similar characteristics are connected and encapsulated to form modules which, in turn, are the basic building blocks of solar arrays. Starting from individual solar cell load curve, the curve of the combination of certain number of cells will preserve the basic series-parallel interconnection laws (Figure 1). Voltage for serially connected elements is the sum of partial voltage across the individual cells and the same current flows through every solar cell. If higher currents are demanded in a system, these can be obtained by parallel connection of the individual strings. In a parallel connected configuration, the

voltage across each solar cell or solar module is equal, while the total current is the sum of all cell or module partial currents. At present, PV generators in grid connected systems work in the range of hundreds volts and amperes.

Fig. 1 Interconnection modes of identical solar cells