One solution to the problem of mismatched cells and hot spots is to add bypass diodes
to the circuit (Standards Australia, 2005). Under normal conditions, for example, with
no shading, each diode is reverse biased and each cell generates power. When a cell is
shaded it ceases to generate, acts as a high resistance and tends to be reverse-biased
by the other cells, causing the diode across the cell to conduct, thereby bypassing the
shaded cell. Fig. 5.12 shows a bypass diode alone, in a circuit and with a faulty cell.
The effect on array output of a faulty cell is shown in Fig. 5.13.