Circuit layout to measure exposure times and/or to control the time of exposure for a photographic camera

Apparatus for the measurement of exposure time and/or for controlling the time of exposure of a photographic camera having a measuring unit responsive to the brightness of an object for generating an exposure time signal at a time when said object brightness corresponds to the proper exposure time of the camera, said apparatus comprising:

• (a) an oscillator providing a constant frequency output,
• (b) a frequency transforming device such as a frequency divider or frequency multiplier connected to said oscillator and having a plurality of output terminals, said frequency transforming device generating at said output terminals different frequency output signals offset in frequency with respect to one another and with respect to said oscillator frequency,
• (c) a timing circuit having inputs connected to receive said different frequencies output signals of said frequency transforming device, said timing circuit providing a plurality of time duration signals, said time duration signals corresponding to and defining non-overlapping, contiguous time intervals,
• (d) an intermediate storage device having signal input terminals connected to receive said time duration signals, a clock input terminal and signal output terminals, said intermediate storage device latching the current time duration signal on its input terminals to its output terminals in response to at least said exposure time signal fed to said clock input terminal,
• (e) display means connected to said output terminals of said intermediate storage device for indicating which of said time intervals is latched by said intermediate storage device, and
• (f) synchronization logic circuit means connected to said oscillator for synchronizing the operation of said timing circuit and said measuring unit,
• whereby said time duration signals indicate which of a plurality of time intervals is appropriate for current exposure.