Abstract: A recorder for placing linguistic character information on photosensitive media. The recorder utilizes a small number of selectively energizable light sources, relative motion between the light from those sources and the photosensitive media, and electronics to coordinate sequential flashing of those light sources to such motion to form individual or sequences of linguistic characters on the photosensitive media. The disclosed embodiment is a microfilm camera that places linguistic characters on microfilm in response to externally supplied character data. The microfilm camera includes a camera box and seven discrete, selectively energizable light sources that are fixedly mounted with respect to the camera box. A portion of photosensitive microfilm is fixed at least temporarily with respect to the camera box. A size reduction lens that is in motion for a period of time focuses light from the light sources upon various areas of the microfilm.

Abstract: An improved switching regulator converts an unregulated DC voltage into a regulated DC output voltage and maintains regulation over the entire range from maximum load current through zero load current. The improved regulator employs a plurality of series switching paths connected between the unregulated DC input and a summing node at a filter capacitor output. Each series switching path includes a power switching element, a catch diode and a series inductor. The other end of the summing node is connected through a current limiting circuit to the DC regulated output, and at least a portion of the voltage at the summing node is fed to a voltage error amplifier and used to control the duty cycle of the series switching elements. Feedback from the current limiting circuit can override the voltage error amplifier control should the maximum current limit be exceeded.