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Circuits designed by David Johnson, P.E.
Last Updated on: Monday, July 11, 2016 01:59 PM

Master Category List - Dave's Circuits

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Burglar/Security Circuits

Alarm Discriminator + Battery Monitor of the Electric Field Disturbance Monitor  -  This schematic is the alarm discriminator plus the batterry monitor of my "Electric Field Disturbance Monitor".  The system can detect human and animal motion by the electric fields they disturb . . . [Hobby Circuit designed by Dave Johnson P.E.,  03/26/02]


Alarm for a Chain Link Fence  -  Long stretches of steel fence can be monitored using the simple circuit below. An insulated wire is woven through the links in the fence.  Where the fence begins, the circuit is connected to an earth ground and the security wire.  At the end of the fence, . . . [Hobby Circuit designed by Dave Johnson P.E.,  10/16/05]

 

Alarm Sounds when Phone Line is Cut  -  Burglars, rapists and other criminals will often cut a phone line before they break into a home.  The cut phone line will prevent many alarm systems from alerting the police.  The battery powered circuit below will sound an alarm when the unit . . . [Hobby Circuit designed by David Johnson P.E.,  10/16/05]


Chain Link Fence Alarm  -  Long stretches of steel fence can be monitored using the simple circuit below. An insulated wire is woven through the links in the fence.  Where the fence begins, the circuit is connected to an earth ground and the security wire.  At the end of the fence, . . . [Circuit by Dave Johnson P.E.,  10/16/05]


Cut Phone Line Alarm  -  Burglars, rapists and other criminals will often cut a phone line before they break into a home.  The cut phone line will prevent many alarm systems from alerting the police.  The battery powered circuit below will sound an alarm when the unit . . . [Circuit by David A. Johnson P.E.,  10/16/05]


Electric Field Disturbance Monitor-Alarm Discriminator + Battery Monitor  -  This schematic is the alarm discriminator plus the batterry monitor of my "Electric Field Disturbance Monitor".  The system can detect human and animal motion by the electric fields they disturb . . . [Circuit by David A. Johnson P.E.,  03/26/02]


Electric Field Disturbance Monitor-Front End + Power Supply Circuit  -  This schematic is the power supply and front-end sections of my field monitor, "Electric Field Disturbance Monitor". The system can detect human and animal motion by the electric fields they disturb . . . [Circuit by David Johnson P.E.,  03/26/02]


Front End + Power Supply Circuits of the Electric Filed Disturbance Monitor  -  This schematic is the power supply and front-end sections of my field monitor, "Electric Field Disturbance Monitor". The system can detect human and animal motion by the electric fields they disturb . . . [Hobby Circuit designed by David A. Johnson P.E.,  03/26/02]


Simple Wire Security Loop Alarm  -  A wire loop is used to protect valuable objects in this alarm circuit.  The circuit is powered by a 9v battery. . . . [Circuit by David A. Johnson P.E.,  12/15/04]


Wire Loop Security Alarm  -  A wire is looped through various objects which are to be monitored.  The loop wire is typically an aircraft cable but could also be any insulated stranded wire.  The loop is attached to a table or desk.  Should the loop be cut, the alarm is sounded . . . [Hobby Circuit designed by David A. Johnson P.E.,  12/15/04]

More  Burglar/Security Circuits
 

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The circuits on this site are designed by David A Johnson - unless otherwise noted.  David A. Johnson & Associates.  All Rights reserved. 
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