FIVE_INDICATOR_ALARM

Published:2009/6/30 1:32:00 Author:May | From:SeekIC

Single five-transistor 10 uses NPN structures on P-type substrate as PNPN silicon controlled switches having common connection for anode (substrate).Relay serving as anode load is energized for actuating alarm if any of the SCS pushbutton switches is closed. Corresponding lamp is energized to identify door or window at which sensor switch has been closed by act of intruder. Alarm remains on until reset by interrupting power supply. Power drain on standby is negligible because SCSs act as open circuits until triggered, permtitting use of batteries for supply. Two or more ICs may be added to get more channels.-H. S. Kothari, Alarm System with Position Indication, Wireless World, Feb. 1976, p 77.



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