Abstract:
A light control system includes a first switching means, a light sensing means, and a flash device. The switching means is selectively operable for providing a contact closure to effect the production of light from the flash device for the illumination of a scene to be photographed. A quench signal to effect the termination of the light provided by the flash device is generated by the light sensing means when sufficient light is received from the scene. The light sensing means includes a false quench inhibit circuit which is responsive to voltage decreases in the voltage supplied to the light sensing means to prevent those voltage decreases from effecting the false generation of a quench signal. Temperature compensation means are also included for automatically compensating the light sensing circuit for variations in temperature, thereby thereby precluding the generation of premature or delayed quench signals which might otherwise be caused by such variations.
Abstract:
An adapter circuit is coupled to a light integrating automatic exposure control circuit of a camera to effect Flashing and Quenching operations of an associated Electronic Flash unit over a two wire connection therebetween. The adapter circuit precludes the transmission of a quench control signal from the camera to the Flash unit until a return signal, representative of a firing of the Flash unit, is received from the Flash Unit.
Abstract:
A computer type flash apparatus includes a switching device, a sensing transmitter and a flash device. The switching device is selectively operable for providing a contact closure to fire the flash device, which, in turn, produces light for the illumination of a scene to be photographed. The sensing transmitter provides a quench signal upon receipt of a predetermined amount of light from the scene. The quench signal is applied through a capacitor to the gate terminal of a silicon controlled rectifier (SCR) to trigger the SCR thereby actuating a quench circuit in the flash device. The operation of the quench circuit terminates the production of light by the flash device. A resistor is connected between the gate and cathode terminals of the SCR. When the flash device is fired, a signal representative thereof effects the appearance of a voltage across the resistor to inhibit noise signals from falsely triggering the SCR until the quench signal is generated by the sensing transmitter.