Image pick=up tube photoconductive film protector for video camera - supplies heating current to filament instead of normal operating current after lapse of operation-free period

摘要

A power supply unit (10) delivers the power required by the camera when a switch (SW1) is closed. The position of this switch is ascertained by a logic circuit (20) delivering a high output, when the switch is closed, to a microcomputer (MC) driving a power control circuit (30). An investigative routine implemented for the operation-free period is followed by a powering routine which supplies normal or preparatory currents timed in accordance with reference intervals. USE/ADVANTAGE - In video cameras and camcorders, damage to photosensitive film is prevented even in presence of getter ions.