In Equation (4), IRS is the cell reverse saturation current in
ampere at TRef, and the solar radiation 1kW/m2. Egap is the
band-gap energy of the semiconductor used in the cell.
A higher power range is required in most practical
applications, so the solar cells are connected in series and
parallel to meet the demand described in Equation (4).
However, only Rs is included in the equation, because the PV
cell is relatively insensitive to the variation of Rsh .Therefore
Rsh is neglected for simplicity with little loss in accuracy.