DiscoverCircuits.com, has 30,000+ electronic
circuits, cross-referenced
into 500+ categories. We have searched the web to help you
find quick design ideas.
We make every effort to link to material posted by the designer.
Please let us if you would like us to link to or post your
design.
The contents &
graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB
SITE server
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 no longer....
Electric
Field Disturbance Monitor
This schematic is the motion discriminator alarm and battery monitor
sections of the field monitor that is discussed in more detail a Electric
Field Disturbance Monitor. (link is off-site) ….
Security Loop
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.
Simple Security
Wire Loop Alarm
A wire loop is used to protect valuable objects in this simple alarm circuit.
The electronic hobby circuit is powered by a 9v battery. The alarm beeper is
activated if the wire loop is severed. The standby current is so low that the 9v
battery should last for many years....
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.
