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 automobile circuit tester is provided having an end connection receivable in the taillight socket, parking light socket, brake light socket or directional signal socket in place of the bulb. When a circuit is completed to the socket in which the tester is received, an audible signal is generated.

Abstract: A method and apparatus for testing ignition systems of internal combustion engines in motor vehicles, in which an ignition voltage signal on the primary side for one ignition operation or averaged for several ignition operations is compared with a should-be signal and the electrode distance of a spark plug is determined in that the should-be signal is taken at the beginning of a service interval and under an operating condition which at least approximately equals the actual operating condition at the point of time of the test.

Abstract: Apparatus for determining the dielectric constant of a fluid as a measure of possible contaminants therein. A reference fluid sample having a known dielectric constant is first placed in a capacitive dielectric sensor and then the fluid to be analyzed is placed in the sensor. By comparing the measured values, an indication is provided of the degree of contamination of the analyzed fluid.

Abstract: A circuit is provided whereby varactor diode is placed in parallel with a capacitance of either the sample or reference cell of a dielectric constant detector. At least the circuitry for applying a voltage to the varactor diode is located outside of the oven in which a dielectric constant detector would typically be located. When the same fluid is flowing through both the sample cell and reference cell, the voltage applies to the varactor diode is manipulated until such time as the capacitance of the sample cell and reference cell are substantially matched as seen by the circuitry which processes the output signals from the dielectric constant detector.

Abstract: A signal generating circuit useful in determining the value of a capacitor includes a charging source having a resistive element and a plurality of switches, each switch being positionable between a first, open position and a second, closed position in response to logic signals. The switches are thereby controllable for sequentially connecting a first reference capacitor of known value and a second capacitor to the resistive element for charging said capacitors to a potential. An oscillating comparator network establishes a trigger reference voltage and generates a clocking pulse when the sequentially detected charge potential of the capacitors is equal to the trigger reference voltage. A logic network is connected to the comparator network for generating the logic signals in response to the clocking pulse and the logic network includes a network for resetting the signal generating circuit.

Abstract: A first process is used to identify the second circuit to which the shorted circuit is connected. A low-level, A.C. potential is imposed between the node known to be shorted and a common trace. A high impedance probe is scanned over the circuits at a distance. The potential detected is filtered and compared with the impressed potential. The result is filtered, amplified, and synchronously demodulated and the result displayed.The second process is used to locate the site of the short. A low-level AC current is injected between two shorted traces. Points along the traces are contacted by a high impedance probe. The signal is filtered and compared with the impressed potential. The result of the comparison is further filtered, amplified, synchronously demodulated and the result displayed.A shorts locator is under the control of a central processing unit. Clips permit connection to the system under test. The clip potentials are monitored.

Abstract: For use with a wiring system having a plurality of wires, a control device having a detector having a plurality of actuatable, observable parts which are numbered, and an electrical circuit coupled with the detector for actuating a specific numbered part thereof when a lead of the circuit is coupled to a particular wire. The apparatus is essentially suitable for use in wiring system in which a plurality of wires extend from respective remote stations to a central station. In one embodiment, numbered resistance modules are coupled to the wires at respective remote locations to assign numbers to the wires, and the control device is at the central station for identifying the wires at the central station by successive actuation of the numbered parts of the detector unit. In a second embodiment, a resistance block is coupled to the wires at the central station to assign numbers to the wires, and the control device is used at the remote stations to identify the wires at such remote stations.

Abstract: An apparatus for measuring changes in the work function of a surface using a method devised by Kelvin and known as the "dynamic capacitor method". This apparatus comprises a system for monitoring and automatically regulating the vibration of a Kelvin probe reed assembly during variation of the experimental conditions. This system includes a piezo-ceramic crystal mounted on the probe support rod to detect the vibrations of the reed and a phase locked loop circuit which compares the signal from the piezo-ceramic detector with the signal of the reed drive coil, interprets a change in the reed resonance as a phase shift relative to the coil drive phase and then shifts the coil drive frequency to maintain the correct phase relationship.

Abstract: Method of determining cylindricity and squareness of mating shaft and bearing members by rotating one member with respect to the other stationary member while using a fluid film as a stiff supporting lubricant to establish a stable and dynamic reference axis, and placing a sensing transducer in the stationary member to measure the variation in distance between the transducer and surface of the rotating member at predetermined increments of rotation and to measure the deviation in squareness in a thrust bearing arrangement. The rotating member is axially translated relative to the transducer and cylindricity measurements made at regular intervals during each of a plurality of revolutions during the axial translation to precisely map the variations in distance to the surface of the rotating member. Squareness measurements are also made under dynamic thrust loading to establish deviations from a true right cylinder.

Abstract: A differential capacitance detector comprising two pulse generators and a comparator. The width of each pulse generator output is representative of the capacity of each of two capacitors whose differential is to be determined. A comparator provides a third pulse whose width is the difference of the width of the pulses input from the pulse generators and is representative of the capacitance differential between the two capacitors.

Abstract: A fail-safe electrical ground indicator is described which includes apparatus for testing whether a vessel or piece or equipment is adequately grounded. The indicator further includes grounded parallel resistors for checking the integrity of the test apparatus, means for making electrical contact between the test apparatus and each of the resistors one at a time, means for making electrical contact between the test apparatus and both resistors at the same time, means for determining whether an electrical current passing through the test apparatus and each of the resistors separately exceeds a specified value, and means for determining whether an electrical current passing through the test apparatus and all of the resistors exceeds the specified value.

Abstract: The diagnostic device comprises voltage divider resistors, two comparators, a start switch, a microcomputer, two transistors, and two light emitting diodes. The ignition signal is voltage-divided by the voltage divider resistors, and the result of this voltage division is input into the positive terminals of the comparators. Reference voltages are input to the negative terminals of the comparators which determine how high the inputs to the positive terminals must be for each comparator to have an "H" level output. When the start switch is turned ON the device starts to operate. In the microcomputer, which has a timer function built in, the interrupt terminal (INT) becomes connected to the output terminal of the comparator; the reset terminal (RES) becomes connected to the start switch.

Abstract: An incremental encoder rotational position detecting apparatus for detecting the incremental rotational position of a rotating member includes a rotatable disk plate rotated with the rotating member, a stationary disk plate opposite to the rotatable plate, and a detector circuit for supplying a rectangular signal to the stationary plate. The stationary plate has first, second, third and fourth electrodes and an earth electrode grounded. The earth electrode is arranged between the first electrode and the third electrode to reduce a distribution capacitance produced between the first and third electrodes. The rectangular signals with opposite phase to each other are applied between the first and second electrodes or the third and fourth electrodes of the stationary plate.

Abstract: A circuit is employed to determine the presence of an open ground connection between a power source and a movable machine connected with the power source by means of a flexible cable. The circuit comprises a pulse generator for transmission of a pulse along the cable between the power source and the movable machine in combination with comparison means for determining whether the reflected pulse back along the cable from the movable machine becomes inverted upon reflection. The presence of a non-inverted reflected pulse indicates an open ground connection. Means are provided for disconnection of power between the power source and the movable machine upon the absence of receipt of an inverted reflected pulse along the connecting cable.

Abstract: An apparatus for detecting a ground fault in an ungrounded DC power supply system having a DC power supply connected by positive and negative lines to a load, an AC voltage is selectively applied between a positive line and ground or between a negative line and ground. A current sensor including an electrical coil surrounding the positive and negative lines is responsive to significant alternating current in one of the lines, when the AC voltage is applied to the line and the line has a ground fault, to thereby indicate the fault.

Abstract: An integrated circuit capacitive transducer measures at least one parameter of a medium to which it is exposed. A variable capacitor has a capacitance which varies as a function of the measured parameter and is charged by source of reference potential. The charge on the variable capacitor is then transferred to a second capacitor having a fixed reference capacitance. The voltage developed across the second capacitor by the charge transferred thereto is then a function of the capacitance of the first capacitor. Therefore, the voltage is also a function of the parameter being measured. The capacitance transducer may also include a further variable capacitor for measuring the difference of parameters between two mediums.

Abstract: An apparatus and method is provided for measuring the continuity and resistance of electric circuits, particularly electric wire circuits used in blasting, in the presence of spurious voltages due to galvanic currents. A constant current from a cell is passed through the electric circuit to be tested and through a reference resistor where the voltages are measured to derive the resistance of the circuit. The measured voltages are sensed with a converter converted to a resistance measurement and displayed. The presence of spurious voltages is compensated for by connecting a galvanic current storage capacitor in the circuit, passing a reference current through the reference resistor and the circuit and comparing the voltage across the reference resistor with the voltage across the circuit and storage capacitor to derive a resistance reading. The reading is converted to a digital display.

Abstract: A unique method and structure is provided for testing high voltage equipment with great accuracy of voltage levels to be measured, repeatability of measured levels from one piece of test equipment to the next, no need for recalibration of test equipment, and sufficiently low current during testing that the test equipment can be powered by the same supply that powers the device under test. The device of this invention can be used to measure not only logical one and logical zero voltage levels of the device under test while under specific loads but can also be used to meausre transition time from one logic state to another.The circuit of this invention provides an output signal which can have three states reflecting a high logic level from the device under test, a low logic level from the device under test, and an intermediate level indicating that the device under test is in transition from one logic level to another or has failed the test.

Abstract: A system for measuring the capacitance of an electric signal conductor, with particular interest on telephone cables. A waveform generator produces a test signal which is coupled to the conductor. The resultant signal emerging from the conductor is delivered to a receiver, and then to an integrator, to produce an output signal which is a direct digital measure of the conductor's capacitance.