photoelectric intrusion detector

photoelectric intrusion detector

[¦fōd·ō·i′lek·trik in′trü·zhən di‚tek·tər]
(electronics)
A burglar-alarm system in which interruption of a light beam by an intruder reduces the illumination on a phototube and thereby closes an alarm circuit.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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