Abstract: A flux monitor high light intensity cut-off circuit for a night vision device which includes a photo detector and an integrator. Incident light striking the photo detector causes its resistance to change, resulting in a voltage change at the photo detector. As long as the photo detector voltage is below a first threshold voltage level, the integrator is inoperative. When the voltage at the photo detector exceeds the first threshold voltage level, this voltage is then applied to the input of the integrator. The integrator then produces an output voltage proportional to the integral of the input current. Once the output voltage of the integrator reaches a second threshold voltage, power to an image intensifier assembly within the night vision device is interrupted.

Abstract: A night vision scope which includes an improved voltage supply. A battery generates a voltage which is proportionally increased by a voltage step-up circuit to provide a voltage to an image intensifier and an infrared light source of the night vision scope. The voltage supply includes circuitry for limiting the voltage output of the voltage supply circuit if a battery is used which generates a voltage greater than that required by the elements of the night vision scope.