Abstract: A method and a device for implementing the method, for geophysical surveying of an area (1) including continuous measurement of the earth's magnetic and electromagnetic field using a detector (6) held at a constant height (E) above the ground surface, in the order of one meter, while traversing in a criss-cross manner over the area (1) at speeds below a maximum speed (S), in the order of 10 km/h, and utilizing measured signal frequencies below a cutoff (F), being approximately the maximum speed (S) divided by twice the detector height (E), to indicate spatial variations in the measured field. Traversal distance can be measured on board the host vehicle and a real time output supplied. Simultaneously, using the same detector (6) and artificially induced magnetic fields generated by an inductive (2b and/or galvanic source (2a)), temporally varying fields having frequencies above the cutoff (F) can be measured and simply filtered out of the detector's (6) output for separate processing and storage.

Abstract: Defects such as corrosion located on a covered metal component are detected through Eddy current inspection using stationary magnetic fields and scanning sensors arrays. A magnetizing yoke is held fixed to the cover of the component and a magnetic flux sensor is used to scan the area between the legs of the yoke over the cover of the component. Also, a fixed array of sensors can be provided between the legs of the yoke for automatic multiplexing of the sensors and sampling in sequence of signal responses picked up by sensors in the sensor array. Additionally, a stationary magnetic field arrangement is provided by a plurality of probes aligned adjacent and parallel with each other. A fixed array of magnetic flux sensors are arranged between the legs of the aligned probes for scanning for defects. This arrangement of fixed sesnsors can be used for underwater use and sealed by a sealing compound.

Abstract: An optical magnetic field sensor is provided that can precisely measure a magnetic field strength without measuremental errors caused by temperature change. The sensor includes a light source, a polarizer, a Faraday's element, an analyzer, a first light beam-receiving element, a first calculation circuit, a second light beam-receiving element, a second calculation circuit, and a third calculation circuit, wherein the light beam emitted from the light source is passed through the polarizer, the Faraday's element and the analyzer in sequence, an S polarized light beam after passed through the analyzer is passed through the first light beam-receiving element, an output signal therefrom is calculated in the first calculation circuit, a P polarized light beam after passed through the analyzer is passed through the second light beam-receiving element, an output signal therefrom is calculated in the second calculation circuit, the third calculation circuit is supplied with the outputs V.sub.11 and V.sub.

Abstract: An ignition distributor cap having a first capacitor for detecting ignition voltage of a spark-ignition internal combustion engine to determine if misfire occurs. The ignition distributor cap has a coil contact tower connected to the secondary winding of an ignition coil of the engine, spark plug terminals connected to spark plugs of the engine, and a rotor connecting the coil contact tower to one of the spark plug terminals with a gap to generate an electric path carrying ignition voltage current produced at the ignition coil to the spark plug. In the ignition distributor cap, a conductor is located around the electric path keeping a predetermined distance from the electric path and forming a first capacitor such that the first capacitor constitutes a capacitive divider with a second capacitor for ignition voltage detection between the electric path and the conductor positioned at the coil contact tower or the individual spark plug terminals.

Abstract: A speed measuring device for use with shallow draft jet pump propelled boats includes a magnetized paddle wheel with diametrically opposed paddles having similar charges and adjacent paddles having opposite charges which is mounted in a housing adjacent a "hall-effect" device which translates the rate of rotation of the paddle wheel into a speed measurement reading due to the changes in the frequency of changes in the electrical field produced by rotation. The present invention is different from all other speed measuring devices in that the paddles do not protrude beyond the outer surface of the hull of the watercraft and therefore cannot become damaged by sand, rocks, or other floating debris. The invention includes a substantially flat base plate with a progressive recess on the underside thereof. This progressive recess carries water to a cavity or housing within which the paddle wheel is rotatably mounted.