Open circuit voltage V oc can be defined as maximum output voltage at zero output current which means whole current flows through the diode (R is infinite). Short circuit current I sc can be defined as maximum output current at zero output voltage which means whole current flows through the load (R is zero). As we can see in figure 1,2 and 3 that I sc varies linearly in proportion with the illumination and V oc varies logarithmically with illumination. On the other hand I sc varies little with temperature and V oc is inversely proportional to temperature.