Electronic shutter with electronically controlled self-timer for photographic camera

Claim 1

An electronic shutter circuitry for photographic cameras, comprising: a first delay circuit connected to a power source for controlling exposure time including a first resistor and a first capacitor connected to said first resistor, a first switch connected in parallel with said first capacitor which opens when the shutter begins to open for causing said first capacitor to begin to charge through said first resistor and initiating the timing action of said first delay circuit when said first switch opens, a first electronic switching means connected to said first resistor and said first capacitor for shifting from a first to second output condition when the charge on said first capacitor exceeds a predetermined value, an amplifier, including at least one transistor, connected to said first electronic switching means and having an output terminal, a single electromagnet connected to the output terminal of said amplifier for controlling the starting of the opening movement of the shutter whenever energized and controlling the starting of the closing movement of the shutter whenever deenergized by said first electronic switching means as it shifts from its first to second condition, a second delay circuit for controlling the self-timing including a second resistor and a second capacitor, a second electronic switching means connected to said second delay circuit for keeping the current from flowing to said electromagnet until this second switching means has been controlled for a predetermined length of time by said second delay circuit, and a second switch connected to the power source and operable to connect said second delay circuit to the power source.