In order to find a method for calculating the optimal gridding of p-n junction solar cells, a distributive-circuitelement model has been derived. It consists of a chain of T elements. They have a resistance in the series path. The shunt paths consist of the diode together with the series resistance, the shunt resistance and the current source. The parameters in the model can be derived from the measurements of the cell under reverse biased, forward biased and illuminated conditions. The model has been employed to derive the optimum stripe separation. This conforms with the prevalent design practice.