Showing papers on "Inductive sensor published in 1981"

Proximity switch with built-in test circuit

Abstract: An inductive proximity switch with a built-in testing circuit for monitoring movable elements in which an oscillator has an inductive control element, the impedance of which varies in response to approaching elements with a built-in electrical tester for monitoring the correct functioning of the proximity switch wherein the tester has an electrically switchable damping circuit for damping the oscillator for test purposes.

Device for measuring local electric conductivity of low-temperature plasma

Abstract: A device for measuring local electric conductivity of plasma, comprising a probe, which is kinematically coupled to a drive mechanism and has a series circuit including an inductive sensor, a measuring oscillator, and a detector having one output coupled, via an optoelectronic converter, to a differential stage having a switch and a memory member. An output of the differential stage is coupled to one input of a measurement recording unit having another input coupled to a unit for feeding commands which is electrically coupled to an electropneumatic control unit accommodating air valves of drive mechanisms of the probe and calibration crystal, the air valve being coupled to pneumatic cylinders of the drive mechanisms by means of flexible bases made of an insulating material.

Capacitively-coupled inductive sensor

Abstract: A capacitively coupled inductive shunt current sensor which utilizes capacitive coupling between flanges having an annular inductive channel formed therein. A voltage dividing capacitor is connected between the coupling capacitor and ground to provide immediate capacitive division of the output signal so as to provide a high frequency response of the current pulse to be detected. The present invention can be used in any desired outer conductor such as the outer conductor of a coaxial transmission line, the outer conductor of an electron beam transmission line, etc.

Object identification sensor and circuit - has inductive sensor coupled to amplitude and phase shift detection circuit

Abstract: An identification system uses an amplitude and phase change to identify either a disc or coin. The sensing stage is provided by an inductive coil (51) through which is passed the object using a guide track. The coil is set at an angle of 45 degrees to the guide path. A resonance circuit (5) is provided by locating a capacitor (52) in series that is supplied with an alternating voltage. The output of the resonance circuit is coupled to a phase comparator (1) and the signal amplified (2) to control a voltage controlled oscillator (3). This controls an amplitude regulator (4). The output is rectified (6) to generate an output to identify the passage of the coin.

Monitoring circuit for vehicle lights - detects failure of light using inductive sensor and switches in second standby light

Abstract: The monitoring circuit has a control (16) associated with both lights (L1,L2). The control receives a signal from an inductive sensor (A) detecting the presence of a current supplying the main light. A changeover switch (20) is operated by the control and switches in the standby light (L2) if the main light (L1) fails (i.e. is open circuit). The signal from the inductive sensor is amplified. The control consists of a monoflop whose control input is connected to the sensor. The sensor consists of an aerial. The changeover switch is an electronic switch (e.g. a thyristor) operating an electromagnetic relay.

Magnetic suspension system for use in satellites - includes low power consumption control circuit providing correcting current to four positioning coils

Abstract: The magnetic suspension system includes a stator and a rotor positioned coaxially forming an annular air gap between them. For each axis the relative positions of the stator and rotor are detected by a capacitive or inductive sensor. This information is used to generate the error signal representing the difference between the actual position and a reference position. Control signals are generated according to the value of the difference signal and applied to the two coils wound on one of the two axes passing at right angles to the common axis of the rotor and stator. In this way the coils are excited where the air gap is too small in such a way as to reduce the magnetic flux there. The control system only uses limited amounts of power, and does not require a symmetrical power source as previous systems do.

Angular transducer for ignition and for injection control - has inductive sensor of magnetised and non-magnetised markers

Abstract: The angular transducer is esp. for controlling combustion engine ignition and fuel injection and has markers on a rotating transducer component detected by an inductive sensor (14). Practically any number of stages can be driven by a single sensor to perform different functions for different angular positions. The transducer is thus simple and economical. The transducer component carries one or more magnetised (14a) and ferromagnetic, non-magnetised markers (11 to 13). A current source (15) for the inductive sensor (14) is switched on by an evaluation circuit (19 to 23) for signals corresp. to the magnetised marker. The current source (15) is switched off by a second evaluation circuit (17,18,24 to 26) connected to the sensor and detecting one or more non-magnetised markers (11 to 13). If several non-magnetised markers are used, a counter (32) ensures that the source is switched off only when they have all passed the sensor.

Inductive sensor for measuring pressure in pipes.

Abstract: Electromagnetic sensor for measuring the pressure in pipelines (21) by means of the pressure-dependent expansion of a magnetic conductive material, in which expansion voltage-dependent permeability changes of the pipeline wall form a measure of pressure changes in the line (21) with the aid of at least one saddle coil (23) fitting closely on the outer pipe wall as inductance changes of the coil (23) measurable in an electrical measuring circuit connected to the coil.

Vehicle fuel consumption optimising device - has inductive sensors for speed and consumption and measurement pulse integrating capacitors

Abstract: A measuring and evaluating unit is for fuel consumption and speed of vehicles and is employed in a fuel consumption optimising device. A processing channel is provided for each measurement parameter and has an inductive measurement transducer connected to its input. The transducer voltage is amplified and fed to a Schmitt trigger which converts the amplified voltage into a pulse signal with steep edges. The pulses are fed to a monostable flip-flop generating pulses of defined duration and amplitude. The flip-flop outputs are passed to analyser integrating capacitors via processing channel power output circuits. The analyser receives consumption and speed signals. The indicator is connected across the two integrating capacitors.

Coin operated gaming machine - uses inductive sensor to provide signals to acoustic generator activated during braking cycle

Abstract: A coin operated gaming machine, of the 'fruit machine' type, has a rotating drum that is brought to rest in a registration position after passing through a controlled braking cycle. The drum carries a disc (1) with a series of projecting stubs (2). A core (3) interacts with an inductance coil (8) that is supplied when the braking contact (7) closes. Signals from the coil vary in voltage dependent upon the speed of the disc. A pulse shaping circuit (10-21) provides pulses for an acoustic generator (9). The acoustic signals vary in frequency as the wheel slows down until the rest position is attained and the winning combination shown.