Showing papers on "Inductive sensor published in 1975"

Intrusion alarm apparatus

Abstract: An intrusion detection apparatus employing two or more diverse types of sensors for sensing entries into a room, building or other enclosure. The sensors are connected to a signal processor which processes sensor output signals to indicate when an intrusion has occured. One type of sensor is a local sensor which includes a sensor conductor in combination with a phase locked loop. Whenever an intruding object is within close proximity to the sensor conductor and disturbs the conductor field, the equilibrium condition of the phase locked loop is disturbed to provide a sensor output signal. A second type of sensor includes in one embodiment an omni-directional antenna having a field which is located in close proximity to or which is overlapping the field of the sensor conductor. Whenever the omni-directional antenna and the sensor conductor are disturbed, the two disturbances are detected by the signal processor to signal an intrusion if the proper time relationship exists between them.

Temperature compensated inductive liquid metal level detection system

Abstract: A temperature compensated inductive liquid metal level detection system and a preferred probe structure is detailed The temperature compensation is provided by provision of a separate temperature compensation coil as part of the inductive probe

Monitor for self levelling headlights - having inductive sensor fitted inside shock absorber to give level control signal

Abstract: The piston rod of the shock absorber is hollow and slides over a ferrite core fixed to the bottom of the damper. The rod is fitted with two induction coils in series and the amount of displacement over the ferrite rod alters the induction of the system and provides a signal for the self levelling control. The system is simple, compact and protected from road dirt and the signal is directly proportional to damper and thus suspension movement.