Abstract: A test circuit is incorporated in a semiconductor memory device including at least one ultraviolet erasable and electrically programmable non-volatile memory cell having a control gate and a floating gate. The test circuit comprises a switching circuit for selectively supplying the control gate of the memory cell with a voltage which is higher than a power supply voltage for ordinary reading a content of the memory cell, through a write voltage supply line used for writing data to the memory cell. The switching circuit makes it possible to test the written state of the memory cell with a voltage different from the normal reading power supply voltage.

Abstract: A device having at least two channels for holding electron packets receives serial data in a first channel. A blocking potential is applied to a set of electrodes to store a set of charge packets with the device. Packets are transferred to the other channel, manipulated and released to travel to an output port. Manipulation operations include arithmetic operations, logic operations, multiplexing and demultiplexing.

Abstract: An open head detection circuit for detecting an open-circuit condition in a magnetic head connected to head contacts. The detector circuit includes a threshold source which generates a threshold voltage that is between a head contact voltage representative of a connected head and a head contact voltage representative of an open head. A comparator, coupled to receive head voltage signals from the head contacts and coupled to the threshold source, compares the head voltage signals to the threshold voltage and generates comparator signals representative of the comparison. Sampling circuitry, coupled to the comparator and coupled to receive write data signals, samples the comparator signals after detection of the write data signals and before the write data signals affect the comparator signals.

Abstract: An apparatus can locate a short between a first and second network with a pair of probes, a measurement device and a current source. The measurement device can measure the potential between the probes. The current source can be connected to the first and second network for injecting between them a current in excess of 1/8 Amp. A larger system can use a matrix connected between a plurality of probes and the measurement device. The matrix can selectively connect a selected one of the probes to the measurement device. This larger system includes a manual keyboard for manually producing a command signal indicating selected pairs of the probes. A processor is coupled to the matrix and the manual keyboard for operting the matrix in response to the command signal to record the potential differences between selected pairs of the probes. A display can spatially display the selected pairs of probes and can also display the polarity of the potential between each of them, as measured by the measurement means.

Abstract: A subscriber line measuring method and apparatus can charge a line capacitance of a telephone subscriber line in a very short time as compared with a prior art by charging the line capacitance by a predetermined current without use of a high resistor (100 k.OMEGA.) in a conventional measuring apparatus, and thereby can measure an impedance of the telephone subscriber line in a very short time with high accuracy.

Abstract: A digital isolation monitor comprises a signal processor operating in conjunction with a measuring circuit to perform a first no-load measurement and a second load measurement of a zero sequence signal delivery by a toroid of a differential transformer, followed by synchronous demodulation, A microcontroller computes the tangent of the angle of phase difference introduced by the toroid by computing the relationship between the load and no-load components, and determines the true values of the leakage resistance and stray capacitance of the power system.

Abstract: Apparatus and method for detecting a location of a break in a conductor of cable, the cable having a multiple number of conductors. The conductors that are not under investigation are connected to ground potential. The conductor that is under investigation is connected to a timer, a resistor, and a DC voltage source that in turn is connected to ground potential. Charging current flows into the conductor under investigation. The time that it takes for the current to decrease to (1/e) of the current's initial value is measured by the timer. Alternately, the conductor that is under investigation is connected to a resistor and a DC voltage source that in turn is connected to ground potential. This conductor is also connected to a voltage level timer that is connected to ground potential. The charging voltage of the conductor increases. The time that it takes for the charging voltage to increase to (1-1/e) of the voltage value of the DC voltage source, is measured by the timer.

Abstract: A method for monitoring for the presence of an electrolyte and for locating the electrolyte upon its presence uses a system comprising an electrically conductive locating member and an electrically conductive source member, between which an electrical connection is made upon the presence of the electrolyte. The locating member and/or the source member comprises (i) an electrode and (ii) an ion exchange material which is in electrical and physical contact with and substantially entirely surrounds all surfaces of the electrode; the ion exchange material having an ionic resistance which depends upon the concentration of a chemical species in the electrolyte. Upon the presence of the electrolyte, a connection to the locating member is made effective at a first point whose location is defined by the presence of the electrolyte.

Abstract: An electric motor controller comprises a circuit for selecting between driving and braking an electric motor in accordance with the health or otherwise of a pair of main electric motor control switches (14 and 16). In a preferred embodiment the health of the switch is determined by the voltage (A) between the switches. The controller also comprises apparatus for detecting the sense of movement of the motor. In the event that the motor is moving in a sense opposite to that selected, the apparatus increase field current to reduce the armature current thereby increasing the braking effect of the motor. Also in the controller are apparatus for changing from armature to field current control and vice versa, in response to a given magnitude of control signal. In order to provide an unambiguous change-over, a lockout circuit is provided to inhibit change-over in a transition region. The lockout circuit maintains the mode of control to above/beneath the change-over level when changing from one level to another.

Abstract: A driver circuit for use in a circuit board tester which tester can perform both functional and in-circuit tests on a given device under test (DUT). The tester provides a test signal representative of a command for the driver circuit to provide logic high or logic low signals to a given device under test (DUT). The driver includes an output stage for providing desired logic high and logic low signals in response to the test signal; and switch circuitry, connected between the tester and the output stage, for preventing the test signal from reaching the output stage in response to a second control signal. The driver circuit is also shown to include an amplifier which, during operation of the driver circuit, receives feedback from the output stage. In addition, the driver circuit includes another output stage which provides a feedback signal when the driver circuit is in tri-state (deactivated).

Abstract: According to the present invention, a method and device for detecting failure of heating elements in various jets of a thermal jet printing device is provided. The printing device which includes a plurality of thermally actuated printing jets, each of which jets includes a resistance heating element, is actuated when a current is supplied to generate a bubble. The bubble expands eject a drop of ink. Electrical circuit means are provided including power supply means to supply current to the electrical resistance elements. Control means are also provided to selectively connect the elecrical resistance elements to this power supply in preselected arrays for forming bubbles in selected configuration to perform the ink jet printing. The operation includes a test circuit coupled to the resistive heater elements and operable by the control circuit to generate a failure signal representative of a resistance above a preselected value in any resistance heating elements.

Abstract: A drive device for an apparatus for electrical function testing of wiring matrices, which has optimally simple electrode shapes for the purpose of a further miniaturization with a two-electrode arrangement. For testing printed circuit boards a non-touching plasma contacting is used whereby two respectively selected measuring locations of a wiring matrix can be contacted via allocated discharge channels and their electrodes. The drive of the measuring locations (test points) occurs via control gas discharges that are generated by applying an adequately high voltage between the electrodes. By applying a voltage between the gas discharges, a current conduction that can be evaluated for test purposes is generated for a conductive connection between the test points.

Abstract: A resistive fault in an electrical cable is located by applying a DC voltage to one end of the faulted cable conductor. The steady state DC voltage and current are measured at the end of the conductor where the voltage is applied. Simultaneously, the DC voltage is measured at the other end of the cable. The voltage is then reversed in polarity and the measurements repeated. Several repetitions of this procedure at each end of the conductor yields sufficient information to compute the location of the fault with reasonable accuracy. The procedure is carried out using two computer-based units, one at each end of the cable, with the two units communicating over the conductor under test.

Abstract: A sensing assembly suitable for detecting both a first event which involves the presence of an electrolyte and a second event which does not involve the presence of an electrolyte, and for distinguishing between them. The assembly comprises a first conductor and a second conductor which is electrically insulated from the first conductor in the absence of both first and second events but becomes electrically connected to the first conductor by either an ionic connection in the presence of a first event or an electronic connection in the presence of a second event. The assembly also comprises a sensing apparatus of determining whether the connection is ionic or electronic. The assembly is useful for detecting leaks of hydrocarbons, e.g. gasoline, and water in storage tanks.

Abstract: A portable bar-to-bar armature tester for testing motor armatures for adequacy of their coil windings is disclosed. The tester is to be held by hand, such that four electrical probes, which extend out of the forward end of the tester, contact with four adjacent commutator bars of the armature to be tested. The tester includes a voltmeter in circuit with two of the four probes, and a toggle switch, a rheostat and a D.C. source in circuit with the two other of the four probes. The circuitry is all housed in a hard plastic casing to protect the circuitry from electrical contact with other objects and to protect the circuitry from damage due to dropping or dirt accumulation. The four electrical probes are laterally adjustable and are contacted with four adjacent commutator bars to determine whether the coil windings, are unbroken and properly wound.

Abstract: A method for measuring line parameters of subscriber lines of a telecommunication system in which end devices, exhibiting a capacitance, are connected to two wires of the subscriber lines is disclosed. The line parameters measured include the capacitances between each of the line wires and ground, the capacitance between the line wires, the leakage resistances between each of the line wires and ground, and the insulating resistance between the line wires. This task is accomplished by performing the following steps while the end device is connected to the subscriber lines. These steps are performed in three measuring configurations sequentially: first one of the two wires of the subscriber line is grounded and the measurement is performed in connection with the other, then the other one of the two wires is grounded and the measurement is performed in connection with the first, and then both wires of the subscriber line are connected together and the measurement is performed on the pair.

Abstract: Breaks in the bare neutral conductor of an underground electric cable can be located by applying an alternating signal across the neutral conductor and a phase conductor at one end of the cable. The neutral and phase conductors are connected together at the other end of the cable. The electrical potential of the alternative signal is measured at a series of spaced apart points on the earth's surface along the cable's path. The potential between points over a cable section with an open in the neutral conductor will be about two orders of magnitude greater than the potential between points above good cable section.

Abstract: A system is described for locating faulty integrated circuits on a printed circuit card under the guidance of computer programmed in accordance with the circuit being tested. The disclosed system includes a current pulsing network allowing digital selection, as by the computer, of reference voltage levels at which current is injected into the circuit being tested.

Abstract: An apparatus for electrical function checking of wiring matrices includes a carrier plate having a plurality of gas discharge channels therein is put in place on a wiring matrix to be checked and selected test locations of the wiring matrix are ionically contacted through the gas discharge channels. Each gas discharge channel is equipped with at least two electrodes and is selectable in accordance with the coincidence principle by electrode bus bars that are preferably arranged in the form of rows so that a matrix addressing of selected test locations can be undertaken.

Abstract: A directional potential analyzer method and apparatus using a non-intrusive electrical measurement technique to obtain a precise location of a leak in a geomembrane liner. The method and apparatus can be used for detecting leaks in either a single layer or a two layer geomembrane liner. The directional potential analyzer comprises a differential voltage detection probe which is moved through the liquid with the potential difference between the electrodes on the probe being measured and recorded as a function of azimuthal position of the probe. An initial scan of the liquid impoundment is used as a reference trace showing all of the anomalies of an unfaulted liner. Subsequent traces obtained by rotating the analyzer probe at a later date are processed and compared with the reference trace to determine the occurrence of new anomalies representing leaks in the liner.