作者: Enrique Rodriguez , Richard Bill
DOI:
关键词:
摘要: A system for detecting the presence of a magnetic field emanating from video display terminal (VDT) in which current induced through sensing element is first amplified by high gain amplifier stage having very broad low band frequency response curve then rectified precision rectifier to convert AC signal DC current. The used as one input comparator, other being set means potentiometer provide flexibility setting threshold voltage differential representative harmful radiation level. output comparator triggers driver connected battery powered solenoid. solenoid actuates an indicator flag exceeds To conserve energy, energized also functions relay break electrical contact between itself and batteries simultaneously with actuating indicator. An alternative embodiment invention replaces pickup coil preferred Hall effect sensor sense strength field.