tokens: Current and Voltage Linearity Test with respect to irradiance and temperature range of interest shall be verified : 1 . The variation of the slope of short circuit to irradiance remains constant within 2 % . 2 . The variation of the slope of open circuit voltage to the logarithm of irradiance [ ln ( G ) ] remains constant within 5 % . 3 . The variation of the slope of short - circuit current and open circuit voltage to cell temperature remains constant within 10 % .