WIRE_CUTTING_ALARM

Published:2009/7/2 3:17:00 Author:May | From:SeekIC

SCR normally acts as open circuit in series with 12-VDC alarm relay because grid is made negative by voltage divider consisting of 100K in series with500 ohms. If ground on 500-ohm resistor is re-moved, as by removal of tape player or CB set from car by thief, gate becomes more posltive and SCR conducts, to energize relay, sound hom, and make headlights shine brightly. Ad-ditional triggering SCRs or alarm switches can be added as shown outside of dashed area for basic alarm.-A. Szablak, Another Burglar Alarm, 73 Magazine, May 1974, p 45-46.



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