Abstract: A normally retracted tip is extendible intermediate spring biased jaws of an electrical probe and is retained in the extended position by a spring bias and the gripping action of the jaws. The housing for the probe includes a compartment for containing interchangeable active or passive circuitry operative upon the signal sensed by the probe or a signal injected thereto from the probe. Apparatus for checking the electrical continuity through the probe is also disposed within the housing. A socket which provides both electrical and structural interconnection between the probe and an attached electrical conductor(s) is disposed at the rear of the housing.

Abstract: An electrostatic voltmeter or electrometer which includes a probe sensor element for receiving electrostatic charge from a test surface whose potential level is desired to be measured. The probe is conditioned to receive both A.C. and D.C. signals which are amplified by a D.C. amplifier, with the A.C. signal from the probe being fed back to the D.C. amplifier to stabilize its output. In a preferred embodiment, a portion of the probe sensor element is periodically exposed to the test surface to impress the A.C. signal thereon which is utilized to correct the drift in the D.C. amplifier output.

Abstract: A probe for the non-contact measurement of electric or magnetic field strengths has two wave guides provided on a substrate. One of the wave guides has a measurement portion consisting of an electro-optical material or a magneto-optical material in a region of a measurement zone. A magnetic or electric field changes the index of refraction of the measuring portion and the intensity of a light wave traveling through this portion of the wave guide is reduced. Comparison is then made between a standard intensity in the other wave guide and a reduced intensity in the light traveling through the wave guide measuring portion.

Abstract: A probe or sensor for an electrostatic voltmeter including a voltage sensitive electrode on the outer surface of a housing wall portion which is vibrated or oscillated by a piezoelectric transducer within the housing and mechanically coupled to the wall portion. The sensitive electrode is moved in a direction generally perpendicular to the plane of the electrode operative surface, the latter being disposed toward an external potential being measured. The capacitive coupling between the electrode operative surface and the external potential is varied at the rate of vibration of the electrode whereby an alternating voltage is induced on the electrode having an amplitude proportional to the amplitude of the external electrical potential being measured. Electrically conducting surfaces in the probe are driven to the same potential as the signal induced on the sensitive electrode.

Abstract: The proposed structural flaw detector is intended for nondestructive testing of continuously moving electrically conducting products, e.g. aluminum, copper and other rods, and comprises two eddy current transducers spaced apart along the path of movement of the products being monitored. One of these transducers is a high-frequency one and is mounted first to detect flaws on the surface, while the other transducer is a low-frequency one and is mounted downstream of the first one to detect structural flaws occurring at a depth under the surface.Arranged between the measuring channels of these transducers is a gating unit blocking the channel of the low-frequency transducer when a surface flaw is detected.

Abstract: In integrated circuits having multiple gate functions, the difference between the propagation delay times of each of the gate functions is often important in that it affects the reliability of the circuits. To determine these delay differences, input signals are applied simultaneously to the multiple gate functions. The output signals of the gate functions are monitored, and a reference signal is generated at the time of sensing the first output signal. This reference signal is indicative of the fastest propagation delay time. A delay time equal to the maximum allowable differential delay time between the fastest propagation delay time and the slowest propagation delay time is added to the reference signal. The delayed reference signal is then compared with the gate function propagation delay time to determine if any of the gate function delays are longer.

Abstract: In electromagnetic testing method for tubes is disclosed, which is used during continuous production of tubing from strip being formed into a tube followed by welding the adjoining edges. A magnetic field is applied from the outside, possibly being a field accompanying the welding process, and a pickup transducer is inserted from the tube forming location to scan the interaction of the penetrating field with the tube particularly the seam and adjacent zones.

Abstract: A diffusion tube hydrogen meter for improving the sensitivity and response time for the measurement of hydrogen in liquid sodium. The improved hydrogen meter has a composite membrane composed of pure nickel sleeve fitted, for example, over a 2 1/4 Cr-1 Mo steel or niobium diffusion tube. Since the hydrogen permeation rate through 2 1/4 Cr-1 Mo steels is a factor of four higher than pure nickel, and the permeation rate of hydrogen through niobium is two orders of magnitude greater than the 2 1/4 Cr-1 Mo steel, this results in a decrease in response time and an increase in the sensitivity.

Abstract: A method for determining the degree of the wear condition of a piston ring in sliding contact with a cylinder wall of an internal combustion engine. The piston ring has a defined magnetic property which property in sliding contact with the wall may be varied by a chromium plating. The reluctance of a magnetic field of an inductive sensor located in the cylinder wall is varied as the piston ring reciprocates and wears. The reluctance variation is compared with a predetermined reference level of the magnetic property for an acceptable degree of wear for the ring.

Abstract: Inspection for hole quality in structures is enhanced by inserting a smooth, thin-wall hollow sleeve into a hole to be tested and moving an eddy current probe within the sleeve. Mechanization is improved by apparatus which inserts and holds the sleeve in the hole and has drive means operable so as independently to rotate the probe or move it linearly, or both, within the stationary sleeve.

Abstract: Apparatus and method is disclosed for determining the position of a mechanical part from among a plurality of discrete positions. An inductor with a saturable core is placed in proximity to each position so that a permanent magnet attached to the part saturates only the core nearest the part, thereby reducing the inductance of that particular inductor. The variation in inductances are detected by comparing voltage rise times across a current limiting resistor serially connected to each inductor. The voltage across the resistor connected to the inductor nearest the position of the part will have the shortest rise time. In a two position embodiment, the variation in rise times is detected by a R/S flip-flop with each input coupled to one each of the inductors.

Abstract: Corrosion at the interface of concrete and reinforcing steel in a concrete structure is determined by placing a hollow hydrogen-permeable probe in the concrete, connecting a getter-ion pump to the probe, and monitoring the output current of the getter-ion pump. An increase in output current is indicative of corrosion occurring at the probe-concrete interface, which in turn is indicative of corrosion at the interface of concrete and steel reinforcing members at comparable locations in the structure.

Abstract: A conductive housing includes a needle for contacting the object whose potential is desired to be sensed. The housing supports an electrometer probe within its confines. In such manner the probe measures the charge on the housing and provides a reading indicative of the potential on the test object without loading it down.

Abstract: An eddy-current crack detection probe is described which allows inspection of turbomachinery parts of conductive material for cracks without removal of the parts to be inspected from the machine or disassembly of the casings normally restricting physical access to these parts. The crack detection probe is particularly useful for field inspections of the trailing edges of turbine buckets of a gas turbine for cracks not readily detectable by optical techniques. The probe, which is insertable through a small opening in the turbomachine casing and thereafter can be remotely manipulated to assume an appropriate inspection position, includes a small eddy-current sensor and may include a borescope for remote viewing of the sensor and turbine bucket edge to be inspected.

Abstract: A magnetic flux standard and method for calibrating magnetic fluxmeters includes the use of a device for measuring changes in the flux of an air gap produced by the insertion into the gap of a magnetically saturable body of known dimensions and magnetic characteristics.

Abstract: A linear variable phase transformer directly converts displacement to phase information. In one form the relationship of such displacement and such phase information is substantially linear or directly proportional. Moreover, a circuit is provided for directly converting such phase information to digital information which is preferably provided in a binary format.

Abstract: An apparatus for and method of monitoring a battery for faulty cells by comparing a pair of input voltages from respective groups of the cells to provide an output signal corresponding to a difference between the input voltages, which initiates an alarm signal when the voltage difference exceeds a predetermined value. To compensate for normal differences between the voltages, the relative magnitudes of the input voltages may be adjusted before the input voltages are compared.

Abstract: A wafer indexing and mapping system is useful for precisely locating artifacts, defects, and fabricated structural components on a wafer. A permanent micrometer grid pattern is applied to the backside of the wafer, for example, a transparent bubble wafer. The grid pattern forms an array of uniform size cells, for example, 40 unit cells wide by 40 unit cells long. Each unit cell is divided into smaller units on each side. Each cell contains a coding or indexing system to identify the row and column of the cell in the grid pattern. The grid pattern contains orientation bars which identify orientation with respect to particular wafer reference lines. The simultaneous viewing of the wafer and the grid pattern permits an accurate permanent mapping of the artifacts, defects, and fabricated structural components on the wafer, as well as on the individual small chips formed by dicing the wafer.

Abstract: A readily portable battery operated eddy current device is disclosed for detecting fissures, cracks or other defects in metal surfaces such as the walls of rivet holes in aircraft parts. Dual sensing transformer secondaries having a high-frequency energized common primary are embedded with pole faces peripherally exposed in a rotary detection probe insertable in a test hole. Differentially connected in a response circuit, these secondaries, constructed with slight mismatch between them, yield a composite response to the presence of a hole wall defect that when differentiated provides a uniquely definitive monopolar pulse of magnitude and relative phase position uniquely indicating on an oscilloscope screen the nature and the precise location of the defect.

Abstract: A method and apparatus for magnetically determining the Gd.sub.2 O.sub.3 content in UO.sub.2 fuel pellets is described. The alternating current susceptibility of fuel pellets within a zircalloy cladding is measured using an ac inductive technique. Ferromagnetic impurity moments are saturated with a direct current magnetic field. Susceptibility increases with increasing Gd.sub.2 O.sub.3 content when the ferromagnetic component is saturated in fields above 6 kOe.