DEVICE FOR DETECTING METAL OBJECTS Russian patent published in 2003 - IPC

FIELD: warning and alarm devices. SUBSTANCE: device has three coils in the form of multiple-turn flat-bed frames forming area controlled in space. Two series-interconnected frames are connected in parallel with third frame and with input capacitors to form parallel resonance-tuned circuit connected to first input of quadrature self-balancing potentiometer designed to generate output signals of desired parameters in case of changes in general inductance, for instance when metal objects are detected in area under control. Proposed device incorporate provision for enhancing sensitivity at the same time reducing external radiation level (power requirement) and for eliminating false alarms in wait mode. EFFECT: enhanced reliability of device. 1 cl, 2 dwg