3_kHz_TONE_LOCK

Published:2009/7/14 22:00:00 Author:Jessie | From:SeekIC

Electric door lock opens only when signal voltage of about 3 kHz is applied to two exposed terminals by holding compact single-IC AF oscillator against terminals. Will not respond to DC or 60-Hz AC. Pocket oscillator operates from 9-V transistor radio battery, with current drawn only when output prongs are held against lock terminals，SCR can be any type capable of handling current drawn by electric lock. -J. A. Sandler， 11 Projects under ＄11, Modern Electronics, June 1978, p 54－58.



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