Digital indication exposuremeter

TLDR: A digital indication exposure meter includes a photoelectric transducer circuit which produces an output current proportional to the intensity of lights incident to a photo-electric element, including a circuit wherein an integrating capacitor is charged up by a photo electric current of the photoelectric element in a manner that the voltage across both ends of the capacitor is proportional to a logarithm of the quantity of light received during a time of light measuring as mentioned in this paper.

Abstract: A digital indication exposure meter includes a photoelectric transducer circuit which produces an output current proportional to the intensity of lights incident to a photoelectric element, said transducer circuit including a circuit wherein an integrating capacitor is charged up by a photoelectric current of the photoelectric element in a manner that the voltage across both ends of the capacitor is proportional to the logarithm of the quantity of light received during a time of light measuring, a timer circuit which produces electric signals corresponding to the time of light measuring, an analog-digital converter which converts the analog output signal of the voltage in the integrating capacitor into a digital form and retains the information in a digital form, a coding circuit which is set to produce digital signals corresponding to film sensitivity, an adder circuit which computes the digital output of the analogdigital converter together with the digital information from the coding circuit, a decoder for converting the digital output from the adder into another digital output suitable for numeral displaying, and numeral displaying devices for indicating the output of the decoder.