Abstract: An input protection circuit protects a multiplexer used in an automotive breakout box for coupling to an electronic control module (ECM) of an automotive vehicle. The input protection circuit includes resistors connected between the input and the multiplexer and a negative feedback amplifier connected to the output of the multiplexer. The negative feedback amplifier provides a virtual ground. Additionally, the inputs to the multiplexer are clamped to within one diode forward voltage drop of electrical ground by diode pairs.

Abstract: A fault detection circuit for a plurality of DC loads uses a reference load as a benchmark. The voltages at the centerpoints of the loads to be monitored are monitored and compared with the voltage of the centerpoint of the reference load. The comparison is affected by faults which do not affect all loads equally (as by a short or open) and is unaffected by faults which do affect all loads equally (as by changes in voltage of the source).

Abstract: In order to take into account the effect of load resistance applied to an electromagnetic field in analyzing an electromagnetic wave oscillator, the present invention arranges a resistance equivalent to the load resistance in the analytical region, and converts a voltage applied to the load and the current flowing therein into an electric field component and a magnetic field component to analyze the electromagnetic field distribution of the entire analytical region. The motion of an electrical charge is thus analyzed taking into account a force applied to the electric charge by the electromagnetic field distribution. This compound analysis of both the electric charge motion and the electromagnetic field is alternately and repeatedly performed.

Abstract: A circuit for measuring variations in the capacitance of a variable capacr forming part of a sensor includes an oscillator which generates an alternating signal which is supplied to two branches of a detection bridge. The first branch includes the variable capacitor connected in series with a variable capacitance diode. The second branch includes a capacitor connected in series with a variable capacitance diode. A differential stage has each of its in puts connected to the common point of a respective one of the branches. Synchronous demodulation means connected to the oscillator, are connected to the output of the differential stage for delivering a DC unbalance voltage Ve which is injected by a feedback line to the common point of the first branch, thereby continuously balancing the detection bridge.

Abstract: A fuse checker particularly adapted for use with miniature, plug-in fuses for testing the fuses while the fuses are in operative position in an electrical circuit. The checker includes a housing from which extend a pair of parallel contact points adapted for engagement with terminal tabs that lie within terminal access openings in a fuse housing. A ground lead is provided for completing the circuit, which includes a pair of light emitting diodes that have their lenses positioned to form part of the surface of a checker housing. A separate, current limiting resistor is applied between a respective LED and one of the contact points and the ground lead. The checker housing can be a hollow structure or it can be solid, to fully encapsulate the circuit elements that are positioned within the housing.

Abstract: An impending failure of an electronic circuit caused by aerosol deposition is detected by using a test circuit including a plurality of conducting paths, aerosol deposition enhancement means, controllable means to control the aerosol deposition enhancement means, conducting path isolation sensing means to measure the isolation of the conducting paths and control means to supply a control signal to the controllable means and warn of impending test circuit failure responsive to conducting path isolation. In addition, the apparatus includes deliquescence enhancement means which is controllable and responsive to the control signal from the control means.

Abstract: Circuitry for testing the ability of an intermediate range nuclear instrut to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on.

Abstract: Load driver system (10) preferably uses a microprocessor controller (20) to generate write/read signals and command signals received by a circuit at write/read and command/status input terminals (16, 17). The circuit (15) responds to the input signals and controls a semiconductor switch (11) that controls the operative state of a load (14). The circuit (15) includes a load shorted high detector (28), a load shorted low detector (29) and a load open detector (30) which are used to detect various faults and provide a predetermined sequence of logic states at the command/status input terminal (17) during read cycles implemented by the controller (20). Thus one input line (terminal 17) is used to both send commands to the semiconductor switch (11) and receive a sequence of logic states indicative of various fault modes. This permits the controller to determine which of several types of faults, if any, has occurred, while minimizing the number of controller-circuit interconnections.

Abstract: A device for measuring and isolating noise-creating imbalances in a paired telecommunications line has an internal circuit which includes a pair of substantially balanced ac current outlet pathways and a pair of high voltage bias pathways in parallel. An oscillator in the circuit generates a low voltage longitudinal ac signal that is transmitted across the balanced pathways and a dc power source simultaneously generates a high voltage dc signal that is transmitted across the high voltage bias pathways. Both signals are further transmitted to the paired line where it is the function of the high voltage dc signal to punch through any concealed faults in the line. In contrast, the low voltage ac signal travels the length of each conductor in the line and returns to the circuit as a metallic voltage signal. If there is any imbalance between the two conductors, the metallic voltage signals for the two conductors will be different.

Abstract: A hot cathode ionization pressure gauge with the following electrodes, arged at a distance from one another in the specified sequence along an axis:(a) a thermionic cathode filament which has a central active part and lateral support parts;(b) an essentially flat, diaphragm-like control electrode,(c) an essentially flat apertured acceleration electrode and(d) an essentially flat ion collector electrode,(e) a base plate on which the filament, the control electrode, the acceleration electrode and ion collector electrode are mounted,wherein the base plate consists of a ceramic material and has a plurality of through holes, and each of said control, acceleration and ion collector electrodes comprises a support member having essentially a shape of an inverted "U" with first and second legs, one of said legs of each electrode support member extending through a corresponding hole of said base plate and being fixed therein.

Abstract: The invention is directed to a connecting circuit for a potential-free lambda probe having a ground line and a signal line and having an offset voltage source which is connected to the ground line. This offset voltage source raises the potential of the ground line to a pregiven value relative to ground. A ground short is directly detectable in the connecting circuit of the invention in that the potential measured at the signal line drops below the offset voltage. In this way, it is no longer required as in conventional circuits to check for a ground short by enriching the mixture of an engine and to monitor the exhaust gas with the lambda probe.

Abstract: Apparatus for detecting an electronegative species comprises an analysis chamber, an inlet communicating with the analysis chamber for admitting a sample containing the electronegative species and an ionizable component, a radioactive source within the analysis chamber for emitting radioactive energy for ionizing a component of the sample, a proportional electron detector within the analysis chamber for detecting electrons emitted from the ionized component, and a circuit for measuring the electrons and determining the presence of the electronegative species by detecting a reduction in the number of available electrons due to capture of electrons by the electronegative species.

Abstract: A direct current power supply applies a positive voltage between the center electrode and the ground electrode of a spark plug in an internal combustion engine after discharge of the spark plug. Ionic current flowing between the electrodes due to the positive voltage is measured by a current sensor. The ionic current caused by the positive voltage is due to electrons, so it has a large magnitude and can be easily measured.

Abstract: The build-up of the deposits on surfaces immersed in water in monitored by passing the water through a galvanic cell comprising a pair of dissimilar metal electrodes (5, 6) mounted on opposite sides of a passage (4) for the water in a housing (1,7), and detecting and interpreting galvanic current developed between the electrodes (5, 6).

Abstract: Methods and apparatus for detecting low impedance short circuits in a secondary winding circuit of a coil of a distributorless ignition system (DIS) by analyzing spark discharge signals on a primary winding of the ignition coil. In one embodiment, the duration times of the spark discharge signals are compared to a threshold spark duration time, with a low impedance short circuit being indicated if the threshold spark duration time is exceeded. In another embodiment, two or more spark dwell signals are applied to the primary of the ignition coil for each spark event of each associated pair of engine cylinders. A first or base time period is determined for the first dwell signal by measuring the time it takes the first dwell signal to produce a preselected current flow in the primary winding. A second time period is then determined by measuring the time it takes the second dwell signal to produce the same preselected current flow in the primary winding.

Abstract: A small, light and portable sensor for detecting and quantifying a harmful high molecular weight substance present in a sample gas in trace amounts is herein disclosed. In the sensor, light and heavy ions are formed by ionizing molecules of the sample gas components in an ionization region. The heavy ions are formed through an ion-molecule reaction. The passage of ions through an ion-passage control region is controlled by directly or indirectly controlling the electric field established between a central electrode and a counter electrode The ions which pass through the control region are collected on a collector electrode. The high molecular weight substance is detected and quantified on the basis of the output from the collector electrode.

Abstract: The state of charge of a rechargeable battery (12), such as those made from lithium, nickel-cadmium or metal hydrides, can be accurately determined by monitoring the rate of change of battery voltage over time (dv/dt), which parameter has empirically been found to change dramatically as the battery reaches complete discharge.

Abstract: The present invention includes a dielectric sensor which provides at least two signals corresponding to the sensed dielectric of a petroleum stream. A temperature sensor also senses the temperature of the petroleum stream and provides a corresponding temperature signal. Crossplot data arrange the two parameters associated with the petroleum stream dielectric is stored in a memory. The memory is accessed using signals from the dielectric sensor and the temperature sensor to select data from the memory. An output circuit provides a water cut signal in accordance with the selected data.

Abstract: While preparing a photographic emulsion a conductivity reading is continuously or periodically taken from the batch during creation. The conductivity of the batch is compared to a standard plot of conductivity versus time representing an ideal batch preparation process. When conductivity of the batch deviates from the standard plot by more than a pre-determined level, an operator can discard the batch, compensate for the deviations, identify the cause of the deviation for use in correcting existing processes and procedures or optimizing future procedures, or compensate for the deviations.

Abstract: A capacitance sensing probe is disclosed for taking measurements of features on a workpiece surface. The probe has two electrodes (E.sub.1, E.sub.2) spaced apart in the direction of movement of the probe with the electrodes being disposed in an attitude normal to the surface. Only the edge of the electrodes are exposed to the surface and an electric circuit (EC) is provided for determining the effect of the surface on the fringe field capacitance between the electrodes. Guard electrodes are used to reduce the stray capacitance being measured. Various embodiments are shown with different numbers and arrangements of electrodes.