Exposure information setting circuit

摘要

The present invention is an exposure information setting circuit for use in photographic cameras which calculates the required exposure time in response to input signals indicative of APEX indices and produces a signal indicative of the exposure time. The circuit is constituted mainly by an integrated circuit which takes advantage of the fact that although the absolute values of electrical characteristics of the circuit elements may fluctuate, particular ratios of such values can be maintained in a predetermined ratio with good precision. This maintenance of the particular ratios can be achieved without requiring any supplementary voltage sources or/and adjustment resistors, whereby large-scale production of the exposure information setting circuit at low cost is possible.