MAGNETIC TRIBOELECTRIC INTRUDER ALARM DEVICE Russian patent published in 2007 - IPC G08B13/26 

FIELD: intruder alarms, possible use for detecting intrusion in controlled territory or in premises of an intruder, carrying ferromagnetic objects with him.

SUBSTANCE: magnetic triboelectric intruder alarm device contains a sensitive element, made in form of a screened cable, serially connected: voltage amplifier, first band filter and first threshold element and second threshold element. Differential voltage amplifier, charge-sensitive amplifier are introduced to device. Screened cable is positioned on guarded object in form of multi-coil loop, beginning and end of loop coils are connected to inputs of differential voltage amplifier, output of which is connected to input of second band filter. Cable screen is connected to zero potential bus.

EFFECT: increased resistance to interference, increased sensitivity and simplified construction of the device.

2 cl, 1 dwg