Abstract: An improved burn-in voltage detection circuit for a semiconductor chip capable of detecting a predetermined voltage level related to a burn-in operation using a specific element irrespective of manufacturing variation, which includes an external voltage detection circuit for detecting whether an external voltage level is higher than a prescribed internal reference voltage level, and in response producing a burn-in enable signal; and a burn-in conversion detection circuit including a hysteresis characteristic, activated by the burn-in enable signal and responsive to the externally applied voltage and the internal reference voltage, for producing a burn-in signal of a first state as the external voltage is increased in magnitude above the level of the prescribed internal reference voltage by a component of the hysteresis characteristic, and a burn-in signal of a second state as the external voltage is reduced in magnitude below the level of the prescribed internal reference voltage by a component of the hystere

Abstract: A probe head includes analog amplifier inputs, a ground plane, and hundreds of probe leads between the inputs and the pins of a circuit under test. The customer defines the grounded pins of the circuit under test. Non-active probe leads, i.e. leads corresponding to the grounded pins are connected to the ground plane, maximizing the connections between the grounds of the probe and the circuit under test and minimizing unequal ground potentials. The probe circuit is on a probe circuit board, while the connections between the ground plane and the leads are fusible elements on a separate ground personality board. The probe is placed on a simulated circuit under test, the grounded pins on the circuit under test are protected by an insulating cap, and a voltage is placed on the remainder of the pins to fuse the elements corresponding the active probe leads.

Abstract: A sensor contactlessly driven by a single power supply is disclosed. A current flows in a resistor R.sub.L through the secondary winding of a coil in the direction corresponding to the direction of magnetic fluxes generated in the coil in accordance with discharge or charge mode of a main battery. The input terminal of a voltage follower is connected to the voltage-dividing point of a series circuit including resistors R.sub.1 and R.sub.2 and a reference voltage control circuit. The reference voltage control circuit changes the input voltage of the voltage follower in accordance with the direction of the current flowing in the resistor R.sub.L. It follows therefore that the measurement range is switched in accordance with discharge or charge mode of the main battery, with the result that the overall measurement range can be widened in spite of the fact that only a single power supply +Vcc is used.

Abstract: A system and method for testing underground electric cables, while in service, for active corrosion and degree of neutral loss. The method is conducted by applying a non-harmonic selected frequency signal to the neutral(s) of the underground cable connecting a pair of structures, e.g., power transformers, from a variable frequency generator of the system. The test is conducted by a surveyor wearing foot electrodes which contact the earth as the surveyor walks along the earth over the cable in close interval steps. At each step, direct current (DC) potentials are monitored by a voltmeter between a copper-copper sulfate electrode carried by the surveyor and brought into contact with the ground at each step and the transformer ground. The potential of the gradients between the foot electrodes at the selective frequency and at the native alternating current (AC) is also measured by the voltmeter. These measurements are recorded at a stationary location on a digital data logger and/or computer.

Abstract: The invention concerns a method for verifying the effectiveness at a given measurement location of a lightning ground system including at least one pick-up member connected to a ground conductor. The method includes the steps of feeding a current to at least one pick-up member by means of an injector device, measuring the magnetic field generated by the ground conductor at the measurement location using a detector device generating a measurement signal the amplitude of which is representative of the magnetic field, and comparing the amplitude of the measurement signal with a reference threshold corresponding to the amplitude of the measurement signal at a reference location a known distance from the ground conductor and in the field of protection of the lightning ground system in order to deduce therefrom, if the amplitude of the measurement signal is greater than the reference threshold, that the measurement location is in the field of protection of the lightning ground system.

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 method for detecting gaps to be bridged in a power supply of an electric rail vehicle includes continuously sensing at least one conductor rail for gaps with at least one contact signal transmitter travelling ahead of a plurality of electrically interconnected real current collectors, as seen in the direction of travel of the rail vehicle, with signal information obtained being stored. An instantaneous contact situation between the real current collectors and the conductor rail is determined from the memory contents. Positions of a virtual current collector travelling in advance are formed for each real current collector from the memory contents, with the distances between the contact signal transmitter and the virtual current collectors being such that a necessity to change over the traction power converter into the regenerative braking mode is indicated as soon as all of the virtual current collectors meet a gap in the conductor rail.

Abstract: An apparatus for measuring an a.c. current flowing in an electric cable comprises a pair of jaws for receiving the cable and which are movable towards one another to engage the opposite sides of the cable. A potentiometer generates a signal ("cable size signal") corresponding to the relative positions of the jaws. A set of coils is provided adjacent the jaws to detect the magnetic field generated by current flowing in the cable. A circuit in the housing is responsive to the cable size signal and the voltage induced in the coil for determining the amplitude of the current flowing in the cable and displaying the same on a display.

Abstract: A dielectric-loaded, microwave sensor which can detect dielectric coatings, e.g., air, water and ice, on a road surface. The sensor includes an antenna having an aperture and also includes a dielectric member with a lower surface and an upper surface. The dielectric member is arranged with its lower surface across the antenna aperture and the sensor is embedded in a road with the dielectric member's upper surface coplanar with the road's surface. An antenna beam, which is incident upon the dielectric member, generates a return microwave signal which is the composite of microwave reflections from the dielectric member's inner and outer surfaces. Air, water and ice can be uniquely identified by the absence or presence of an amplitude minimum at predetermined frequencies of the return microwave signal. The thickness of an ice coating is determined by observation of the frequency of the amplitude minimum.

Abstract: The dynamic range of a current transformer (CT) is increased without reducing the scaling of measurements at the low end of the dynamic range by designing the core of the CT to saturate only after about 90 electrical degrees of the maximum current to be measured. The measurements taken during this first 90 electrical degrees before the core saturates are doubled to in effect add measurements representing the mirror image of the first 90 electrical degrees. Timing of the digitized samples taken during the first 90 electrical degrees is adjusted to account for core reset energy errors, by determining the rate of change of current just after a zero crossing and selecting an empirically determined value of current for timing the start of the measurement samples.

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.

Abstract: A capacitance sensor assembly for use with a label detection and registration system for detecting a lateral edge of a label on a web bearing a plurality of such labels and moving in a longitudinal direction through a capacitance gap in the sensor assembly. The capacitance sensor assembly includes a reference plate electrode, and a pair of sensor electrodes extending substantially parallel to and spaced apart from the reference plate electrode to form the capacitance gap. The pair of sensor electrodes has a differential capacitance, when the web bearing the plurality of labels thereon is in the capacitance gap, which is used to provide a signal indicative of the lateral edge of the label.

Abstract: A conductive strip detector comprises a capacitor defined by an elongate, electrically conductive element (5) and a laterally spaced, electrically conductive member (1). Monitoring circuitry (15,16) monitors changes in the capacitance of the capacitor when an electrically conductive strip substantially parallel with the element is passed by the capacitor and indicates when a change in capacitance is due to the presence of an electrically conductive strip.

Abstract: A circuit continuity test device is disclosed. The device utilizes a series circuit to provide a completed circuit for an external explosive or pyrotechnic circuit. The series circuit has a switch in the form of a light emitting diode and a power source. Upon coupling to a continuous external circuit, the diode is placed in an on state thereby illuminating and indicating a continuous external circuit.The device housing is a simple, compact and solid part. This allows the device to be used in a variety of environmental conditions and easily and inexpensively manufactured.

Abstract: A semiconductor device test system for efficiently testing many types of devices and for reducing the amount of floor space needed. The test system has a test board having a plurality of sockets for receiving semiconductor devices. A semiconductor device insertion and extraction station removes the devices from a tray and inserts them into the sockets of the test board and extracts the devices from the sockets to mount them on the tray. A test chamber has a temperature setting section for setting the test board to a test environmental temperature and a test-performing section for supporting the test board so that electrode terminals of the sockets are exposed. A tester head is simultaneously connected to the electrode terminals of the sockets of the test board. A head moving section connects the tester head to the electrode terminals of the sockets of the test board. A tester is connected to the tester head to test electrical characteristics of the semiconductor devices.

Abstract: An apparatus for positioning a workpiece comprises a plurality of pedestals each comprising a first portion having a first width, a second portion having a second width greater than the first width, and a chamfered portion interposed between the first and second portions. The inventive apparatus further comprises a support having a plurality of holes therein for receiving the plurality of pedestals, the support further having a plurality of chamfered portions with one the chamfered portion about a periphery of each the hole. A base urges the chamfered portions of the pedestal away from the chamfered portions of the support.

Abstract: A test instrument for testing magnet wire which is provided which tests, collects and permits analyzing the effect of temperature, frequency, voltage and rise time associated with magnet wire use, and more particularly, the effects of those variables on the insulation of the wire, so as to evaluate the magnet wire performance and inverter controlled dynamoelectric machine applications.

Abstract: An apparatus and method for determining the state of a switch for use in an HVAC system. The apparatus and method are advantageously configured for use within a heating, ventilation and air conditioning (HVAC) system, in which the sensing of the state of safety switches external to a controller is desirable. A current sensor coupled in series between a current source, a safety switch, and a current load, detects the flow of current from the current source and through the switch and load. A status signal, indicative of the flow of current through the current sensor, is generated for sampling by a microprocessor. The presence or absence of current flow through the current sensor provides an indication as to whether the remotely-located switch is in an open or closed state.

Abstract: A capacitive fluid level sensing pipette probe adapted to be used in an automated random access immunoassay analyzer is provided. The pipette probe comprises an elongated shaft having a conductive tip. An integrated circuit chip containing capacitive sensing circuitry is positioned on the pipette probe itself, or in very close proximity. With this arrangement, the sensing circuitry moves with the pipette probe as it is raised and lowered into and out of a vessel containing a liquid. Thus, errors associated with capacitance caused by flexing connector cables is eliminated. Flex tape wiring may be used to carry data from the capacitive sensing circuitry on the pipette probe to the processing board of the automated immunoassay analyzer.

Abstract: A method and apparatus for locating an incipient fault at a point along the length of an insulated power line includes the application of an excitation voltage at an open end of the power line, and the signal pulse transmitted along the power line to the open end is passed through a high pass filter to remove the portion of the signal which is at a frequency below the excitation voltage and its harmonics. The filtered signal is amplified and passed through a band pass filter to remove a high frequency portion of the signal containing a large proportion of noise relative to the frequency of the partial discharge frequency from the incipient fault. This filtered signal is passed to a digital storage device adapted to be triggered by a signal of a predetermined amplitude, and the triggered digital storage device receives the amplified signal directly from the amplifier and stores digital data concerning amplitude and time for the peaks of the amplified signal for a predetermined period of time.