The strength that uses up the electricity to receive the machine to measure the light is in accordance with shine on the degree the hour, for the sake of make receive the machine see see function and person's eyes see see the function, must take into the correction, seeing to see the function correction glass be use to revise the light electricity to receive machine( such as selenium, the light battery, photoelectric cell) and person's eyes to see to see the function of difference.Various different light electricities receive the machine, applying the different glass to revise.After chart showed to add to revise the glass of a curve of the selenium light battery spectrum.