Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.

Abstract: The identification of and compensation for changes in the dielectric properties of a hydraulic fluid in hydraulic apparatus is achieved by continuously sampling a hydraulic fluid in a resonant chamber with a central conductor that is both inductively and capacitively coupled to an oscillator. The output frequency changes of the oscillator is an indicator of changes of the dielectric properties of the hydraulic fluid and their magnitude. The invention is of particular value in hydraulic cylinder piston position determining systems.

Abstract: The invention relates to an apparatus for measuring the capacitance between at least a conductive part of a wall of a vessel and a measuring electrode situated in the vessel and carrying a measuring voltage, comprising a measuring circuit and a compensating circuit for applying a compensating voltage as nearly as possible the same as the measuring voltage to conductors present in the vicinity of conductors carrying the measuring voltage, wherein the capacitance between the measuring electrode and the vessel wall is connected as frequency determining element in an oscillator, so that the frequency of the measuring signal is related to the value of the capacitance. Frequency is a quantity which can be measured much better, can be determined much more precisely, requires less complicated circuits and can be largely implemented in integrated form.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: A non-packaged semiconductor chip testing apparatus includes a lead frame having chips with a plurality of leads which are electrically isolated from the other leads, and are supported by adhesive tape and bonded to the chip via wires. The lead frame is placed on a holding plate having windows, so that the leads of the lead frame are exposed through the windows and contact test probes located under the plate. The test probes, such as pogo pins or bending leads, extend upwardly from a substrate. A base receives the substrate, with cables extending from a lower surface of the substrate passing through openings in the base, where they then connect a test board. After being pressed down by a pressing cover, the lead frame on the holding plate moves down so that the leads may contact the test probes. The pressing cover is movable up and down. Guide pins on the base are simultaneously inserted into through holes of the holding plate and lead frame, and extend into recesses in the pressing cover to ensure alignment.

Abstract: A system for determining the position of a piston moveable within a cylinder, or of an implement or joint, is disclosed herein. Electromagnetic (EM) bursts such as ultra-wideband or frequency pulses are generated and applied to a transmitter/receiver unit. The EM bursts are launched by the transmitter along a transmission guide from an end of the cylinder housing towards the piston. The transmission guide can be a dipstick mounted within the cylinder housing or the cylinder housing itself. The dipstick or cylinder housing is in electrical communication with the piston such that a surface of the piston represents an electrical impedance discontinuity which causes the EM bursts to be reflected back to the receiver. The time for the EM bursts to travel from the transmitter to the piston and for the reflections to travel back to the receiver is determined and converted into a position signal representing the piston's position.

Abstract: An automatic circuit board tester for testing for shorts, opens, and interconnected pins or nodes on a circuit board. The tester first classifies the nodes as being in one of three categories based upon the design of the board and the intended interconnection of the nodes. The categories of nodes are: (1) connected to ground; (2) interconnected to all other nodes in the test group; or (3) isolated from all other nodes. The circuit board tester has a testhead containing a plurality of test channels, each configured to be coupled to a node on the circuit board. The testhead utilizes a digital signal from a digital driver to drive the node, at a predetermined voltage and a digital receiver to read the node voltage to determine if it is coupled to ground. Each test channel also includes a switch to connect the digital driver and receiver to the test node as well as a ground switch to selectively couple the node to ground.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: A transducer is disclosed which provides distance or position information about a target relative to the transducer. The transducer has first resistor and a first electrode for forming a first capacitive coupling with a target, a second resistor and a second electrode for forming a second capacitive coupling with the target. Signals of opposite phase or polarity are applied to the respective resistor electrode combinations. By applying signals of opposite phase or polarity, no net signal is applied to the target, thereby avoiding problems with cross talk between adjacent transducers.

Abstract: An electrostatic sensor comprises a ground electrode defining an enclosure having a through-hole for permitting the passage of a body therethrough. A sensor electrode is disposed in the ground electrode. A detecting circuit is disposed in the ground electrode for detecting the passage of the body through the through-hole on the basis of a change in an electrostatic capacitance between the ground electrode and the sensor electrode.

Abstract: A system and method for detecting and controlling ungrounded parts during the electrostatic coating process in order to improve production flow, provide an overall cost saving by efficient use of the coating material and prevention of accidental fires and false shutdown during production. The system of the present invention comprises a detection system for detecting any ungrounded parts prior to entering a coating environment, such as a painting booth. The detection system in accordance with one embodiment, comprises an array of detectors, specifically, an ultraviolet sensor, a radio-frequency wave sensor, an acoustic sensor and a light sensor, which upon sensing specific characteristics generate representative signal waveforms. These waveforms are than compared with stored waveforms relating to profiles of sparking or corona discharge characteristics. Correlation circuits may correlate data obtained by two or more sensors in order to ensure that the spark or corona discharge is caused by an ungrounded part.

Abstract: Method and apparatus is described for detecting faults, such as cracks, in ink jet printhead heater chips using a resistor on the heater chip. The resistor is located adjacent to at least one edge of the heater chip. One method, for example, includes the steps of measuring the resistance of the resistor at a first temperature and comparing the measured electrical resistance to a theoretical calculated resistance. Another method, for example, includes the steps of measuring the resistance at a first temperature, heating the chip, and measuring the resistance at a second temperature. Faults are detected by comparing expected changes in resistance or temperature to measured changes.

Abstract: In a moisture sensor arrangement for large area layers including a high-frequency electrical generator, a signal travel time measuring apparatus and a reflectometer, all connected to a cable system, at least two independent cables of the cable system are arranged so as to have cross-over points with, and being disposed in spaced relationship but sufficiently close t, one another such that a signal transfer can occur at the cross-over points.

Abstract: An intravehicular auto harness tester with switch consisting of a first housing unit mountable within or upon the dashboard of a motor vehicle containing three small light emitting diodes with wiring leading thereto and therefrom coupled with one resistor per diode, with such wiring entering the housing unit and leaving it by way of a coaxial cable leading to or from a second housing unit located typically in the trunk of the vehicle with three prongs and female socket pocket at a front end of the second housing unit for interfacing with an intravehicular auto harness power plug and with three female socket pockets and a prong at a rear end thereof for interfacing with a trailer harness plug and with wiring therein running from prongs to socket pockets and via junctions along such wiring also from the front end prongs to wiring in the coaxial cable leading to the diodes and a ground wire within the cable leading via an off/on switch from the diodes to the front end socket pocket of the second housing unit alo

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.

Abstract: The invention relates to a method of monitoring anti-lightning protection equipment that includes a grounding line (1), the method being characterized in that a "lightning" electrical current travelling along the grounding line is measured. The measurement may be obtained, in particular, by means of a magnetic circuit (2) constituting a closed loop around the grounding line, and electrical circuit that includes a winding (5) disposed around the magnetic circuit so that a lightning current travelling along the grounding line induces current in said winding, the magnetic circuit including a core (3) of solid magnetic material that has at least one gap in the magnetic circuit, said gap being occupied by material that is not magnetic.

Abstract: A method for locating a fault in an electric power transmission line to form measured precursor fault vector values of two aerial modes from sample values from currents and voltages stored immediately before and during an occurrence of the fault, using the Clarke transformation. For synchronization, the phase angle is determined from these measured vector values, so that fault vector voltage values of both aerial modes can be generated without distortion by asynchronously forming the sample values. The fault vector voltage values of one aerial mode are subtracted from those of the other aerial mode, and the resulting differences are squared. The location of the fault is determined by estimating the minimum value of the sum of the squared differences.

Abstract: Determining the location of an ESD event is achieved through the use of an envelope detector or absolute value comparator which identifies the arrival of an electromagnetic waveform generated by an ESD event at each of a plurality of antennas. Arrival times are compared to determine the location of the ESD event. A plurality of N antennas are employed, and each antenna is coupled to a corresponding envelope detector, threshold discriminator, switch, and register. The output of a clock is coupled to the switches, and a microprocessor is coupled to the registers. When an antenna receives a waveform corresponding to ESD, the envelope detector extracts an envelope signal related to the envelope of the waveform and couples the envelope signal to the threshold discriminator. When the envelope signal has a value above a specified threshold, the threshold discriminator sends a signal to latch the current count of the clock into the corresponding register.

Abstract: An apparatus for contactlessly measuring the electrical resistance per unit ength of a low-resistance test conductor (e.g., wire or cable) at a selected measurement frequency, which includes a coaxial cavity structure having a central cavity region defined by opposed first and second outer conductor sections, and a center conductor, wherein the test conductor comprises the center conductor. An input probe disposed adjacent to the first one of the outer conductor sections launches a standing wave on the center conductor, and an output probe disposed adjacent to the second one of the outer conductor sections senses the Q of the central cavity region. A detector coupled to the output probe measures the sensed Q of the central cavity region. The electrical resistance per unit length of the test conductor at the selected measurement frequency can be determined from the measured cavity Q.