Abstract: A voltage gradient measurement device is provided for determining the remaining lifetime of a battery used to power a radio, pager, cellular telephone, or similar device. The battery is attached to a first circuit element to obtain a history of the battery voltage which is used to determine the differential battery voltage. The battery is also attached to a second circuit element which measures the voltage margin between the battery voltage and a reference voltage representing the battery end-of-life condition. A third circuit element divides the voltage margin output of the second circuit element by the differential battery voltage output of the first circuit element to estimate the time that will elapse until the battery voltage approximately equals the reference end-of-life voltage level.

Abstract: A protective grounding jumper cable tester basically includes a housing, a direct current power supply, a pair of jumper attachment terminals, a pair of test probe terminals, a current applying circuit connected between the direct current power supply and the pair of jumper attachment terminals for applying a direct current through a jumper cable attached between the jumper attachment terminals, and a resistance sensing circuit connected to the test probe terminals for sensing resistance to the flow of the direct current through the jumper cable by using a pair of test probes connected to the test probe terminals.

Abstract: A wet/dry hot stick tester designed to provide a dry test of a hot stick by applying a voltage equivalent to 100 KV/ft to the hot stick, and to provide a wet test of a hot stick by applying a voltage equivalent to 75 KV/ft thereto. Output electrodes are positioned along a reading aperture provided in a housing of the hot stick tester, in which a hot stick being tested is positioned. A two tap transformer has a first input tap for providing a first voltage equivalent to 100 KV/ft to a hot stick positioned in the reading aperture during a dry test thereof, and has a second input tap for providing a second voltage equivalent to 75 KV/ft to a hot stick during a wet test thereof. An ammeter measures the leakage current through the hot stick during an applied voltage. A wet/dry switch switches the two tap transformer between the first and second input taps.

Abstract: An apparatus for checking the authenticity of a security document (28). The security document (28) comprises a base material and in its volume particles having some electromagnetic properties which are substantially different from the corresponding electromagnetic properties of the base material. The apparatus comprises at least one emitter (18) for emitting near infrared or visible waves to the document (28), at least one detector (20) for detecting any of the emitted near infrared or visible waves reflected from the document (28) and means (30) for processing the detected near infrared or visible waves in order to differentiate the security document (28) from a document comprising electromagnetic particles or parts on its surface.

Abstract: The position of a break in at least one of a pair of rails in an electrically isolated rail segment of a railroad is carried out by measuring current across the ballast between the rails of the segment from one end of the segment when one of the rails in the segment is not broken and subsequently when the rail is broken. A position of the break can be calculated as a function of the ballast current. A linear approximation using the ratio of the ballast current when the rail is broken to the ballast current when the rail is not broken multiplied by the distance of the rail segment from the one end gives a satisfactory approximation of the location of the rail break.

Abstract: An electromagnetic induction-type probe, for measuring the electrical properties of a solution, exhibits both a reduced size and a wide band property. The probe includes a primary transformer, composed of a toroidal core with a primary coil winding, a secondary transformer composed of a toroidal core with a secondary, coil winding, an electrostatic shield and coaxial cables which connect the probe and the main frame of a measuring instrument. The structure of the probe is symmetrical in order to eliminate measurement errors due to the asymmetry of the electrical field produced in the solution. The symmetry of the electrical field in the solution is maintained up to the high-frequency region and a wide-band effectiveness is realized by connecting the center tap terminal of a balancer to the outer conductors of the coaxial cables and the other terminals of the balancer to both ends of the gap of the electrostatic shield.

Abstract: A plurality of electrical circuit components having capacitance, e.g. ceramic capacitors, are tested simultaneously in a corresponding plurality of test channels. They are stressed by a variable voltage source that can produce an electrical potential selected from a wide range from low potential to high potential. For example the range of selectable potentials can be 1000 volts with a resolution of 1 volt. The charge current by which a component accumulates a charge is controlled to a selected linear rate by a current controller. Voltage sensors and current sensors measure accumulated charges and leakage current, respectively. The current sensor can be selectively sensitized to a plurality of anticipated leakage current ranges. In addition, the selected potentials can each be applied to the components in a single step or can be applied over time in ramp fashion.

Abstract: In a method of detecting deterioration of a battery pack consisting of a series assembly of a plurality of battery modules during charging, on the basis of a voltage difference between a plurality of battery modules, deterioration detection is inhibited until a predetermined capacity is charged after starting of the charge. Also, in a detection apparatus for deterioration in a battery pack according to the present invention, a deterioration reference discharge voltage value which should correspond to a discharge current value and a temperature value is calculated on the basis of reference data, and the deterioration reference discharge voltage value is compared with an actual discharge voltage value to judge whether deterioration occurs or not.

Abstract: When a car is moved, a current and a voltage from a battery change and a power-supply voltage of a sub-battery is not lower than a manipulation level, an approximately linear function is obtained according to a current from a buttery and a terminal voltage, and residual capacity is displayed according to the approximately linear function. When the car is stopped and the current and the voltage of the battery do not change, the residual capacity is obtained according to the voltage. Moreover, when a power source supplying control circuit judges that an ignition is turned off, a voltage of the power source is lowered to the manipulation level so as to be supplied for prescribed time required for the battery becoming constant.

Abstract: An ergonomically designed pistol grip voltage probe testing device features visual output indicators, such an LED light, as well as at least one additional or auxiliary indicator such as a buzzer. The LED advantageously changes colors depending on the potential applied to the probe conductor. Other auxiliary output feedback devices are disclosed. The device is particularly suitable for use in an automotive environment, and, in one embodiment, includes a cigarette plug adapter for connecting the device to a cigarette lighter receptacle for supplying output power and a ground reference potential to the test device.

Abstract: A returned reference compatible straightaway envelope delay measuring instrument and a related method use a sinewave generator to produce an envelope and a low frequency reference oscillator for modulating amplitude of the envelope. The low frequency modulated envelope signal is transmitted over a transmission path to an envelope detector, which detects the envelope. A phase detector connected to the envelope detector and to a local similar low frequency reference oscillator detects phase difference between the low frequency modulating oscillation in the envelope and a local reference oscillator signal. A processor makes a series of delay measurements and computes the delay difference between the start delay measurement and the end delay measurement.

Abstract: A method of detecting when a moving component of an electromagnetically operable device attains a final position after de-energizing a winding of the device comprises allowing the energizing current to fall to zero and prior to the component reaching its final position, connecting a sensing circuit in parallel with the winding, the current flow in the sensing circuit increasing from the instant of connections and decreasing when the component reaches its final position, said sensing circuit detecting the change in current flow.

Abstract: A testing apparatus for detecting popcorn noise in magnetic heads comprises a fully integrated testing system which includes an analog circuit portion and a digital circuit portion. The analog circuit portion is implemented to interface with a magnetic head while the digital circuit portion is designed to store the testing sequence, analyze the testing data, control and execute the testing routines. The testing apparatus is designed for production environments where testing data are required instantaneously as feedback for production process monitoring.

Abstract: A method is used which reduces measurement errors, especially of permittivity, which result when electromagnetic induction-type probes measure electrical properties of solutions. Part of the electromagnetic induction current, which the electromagnetic induction-type probe tries to induce in the test solution, flows in the stray capacitance, which is formed by the dielectric in the probe. This partial current reduces the current that is linked to the current detector transformer, and affects the measured value of the electrostatic capacity component, i.e., the permittivity, of the test solution. This phenomenon is modeled and is expressed by a distributed constant circuit which is simplified to a T-shaped 2-terminal pair equivalent circuit. A correction equation that corrects the errors due to the aforementioned currents is obtained by means of this simplified equivalent circuit, and the measurement errors are reduced.

Abstract: An RF detector circuit (28), which may be utilized in an output power control loop (10) for an RF transmitter, includes a bridge circuit (50) including a first arm (52) containing a first diode (D2) which rectifies the RF signal and a second arm (54) which contains a second diode (D3) series-coupled to the first diode (D2), and having an RF bypass capacitor (C4). The second diode (D3) serves as a temperature compensator for the first diode (D2). The outputs of the bridge circuit (50) are connected to the inputs of a differential amplifier circuit (32) which provides a signal for use in the power control loop (10). The detector input signal is derived from the sense output of a directional coupler (22). In a second embodiment the compensating diode (D13) has its cathode coupled to the cathode of the rectifying diode (D12), and the full voltage across the rectifying diode (D12) is applied to the differential amplifier circuit (32).

Abstract: A method and apparatus for detecting and indicating the number of times a CRT unit arcs. The apparatus is constructed of a ferrite split toroid core wound with wire which is coupled around the focus lead and/or ground lead of a CRT through which a current spike will occur during an arcing event. The wound wire is coupled to a current pulse detector which in turn is coupled to a monostable mode timer and counter for counting the number of arcing events. The counter is coupled to a display device for displaying the number of times the CRT has arced.

Abstract: Apparatus for measuring the surface resistance and electrical resistivity of a homogeneous, resistive material sample includes a measuring cell having a sample location able to receive the sample and several electrodes in the form of knives placed on the same side of the sample and guided in an insulating block whose ends are positioned on the sample, the pressure necessary for establishing good electrical contacts between the electrodes and the sample being ensured by a shim which urges the electrodes toward the sample. A first pair of the electrodes make it possible to inject a current into a sample to be tested and a second pair of the electrodes make it possible to collect a voltage from the sample.

Abstract: A circuit to monitor a short circuit (or a line interruption) in an inductive circuit which is connected to a signal-processing circuit through a high-ohmic filter circuit. The monitoring circuit is formed as a component part of or as an additional element to the signal-processing circuit and initiates a test cycle to determine the inductance of the circuit to be monitored when, for example, the ignition of an automotive vehicle is turned on when the inductive circuit is used in the circuitry for sensing wheel rotation behavior of an automotive vehicle.

Abstract: A cell tester device for use on an electrochemical cell which comprises a printed transparent electrically conductive electrode disposed on a plastic film, an ionically conductive electrochromic electrolyte printed on the electrode, and a conductive layer printed on the electrolyte.

Abstract: A non-ferrous current sensor is used to continuously measure the charging current magnitude in step-graded foil and paper insulation systems and capacitive insulation systems used on high voltage measurement and control apparatus such as instrument transformers and on the condenser bushings of power transformers and circuit breakers. The low voltage measured signal is conditioned by an electronic circuit that modulates a DC signal in a system current control loop to provide continuous remote monitoring and alarm functions. Remote power is supplied to the sensor and conversion circuits through the current loop. The sensor detects changes in the charging current through the insulation ground conductor, indicating the degradation of the dielectric properties between the foil layers. The sensor and associated electronic circuitry are enclosed in a housing adaptable to be used with a capacitance tap common to high voltage measurement and control apparatus.