Fill factor is an important performance metric for photovoltaic cells. It is defined as the ratio between the maximum power output, Pmax, and the characteristic power product 
The ideal fill factor, FF0, is defined as the ratio between the maximum output power and the ideal output power. The ideality refers to that of the diode in the equivalent circuit.
Ideal equivalent circuit here. Where it comes from, why it's important, relationship with operational efficiency. Derive FF as a function of V (dP/dV = 0 gives Vm, Im - put this in maximum power point tracking and refer to it to get FF0).
Effect of Rs and Rp on FF. Derive new FF relationships, curves showing effect.
This isn't correct yet, I just put Green in because it's good and I'll use it!
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Category:Engineering ratios Category:Solar cells
