Abstract: In the case of a circuit arrangement with a flow probe operated in a bridge circuit, a device for determining bridge balance, which controls a triggering circuit which can be supplied by an oscillator and controls a switching device for the power supply of the bridge circuit, the oscillator has an operating frequency which is at least approximately inversely proportional to the square of the operating voltage of the power supply.

Abstract: An optical transformer comprises at least two potential dividing capacitors connected in series to each other are connected between a high-voltage conductor and an intermediate electrode or between the intermediate electrode and the ground, and optical voltage sensors connected in parallel to the respective potential dividing capacitors and capable of modulating light in accordance with voltage. In another form, the optical transformer has a single potential dividing capacitor connected between a high-voltage conductor and an intermediate electrode or between the intermediate electrode and the ground, and at least two circuits connected in parallel with the potential dividing capacitor, each circuit including a series the connection of an optical voltage sensor for modulating light in accordance with the voltage and a resistor or an impedance.

Abstract: A voltage potential monitoring circuit is operative to set a voltage potential threshold substantially independent of ambient temperature variation. The monitoring circuit includes a first circuit for generating a first current proportional to the voltage potential being monitored, and a second circuit responsive to the first circuit for generating a second current. The voltage potential threshold is set substantially as a function of the first and second currents. The monitoring circuit further includes a circuit responsive to the first and second currents for generating an undervoltage signal when the monitored voltage potential falls below the set voltage potential threshold. The voltage potential monitoring circuit has application in an electronic device which is operational over an ambient temperature range and includes a source of power for generating a voltage potential suitable for energizing the electronic device.

Abstract: Disclosed is a measurement method and apparatus by which measurement of the breakdown voltage of a semiconductor device under test (DUT) may be conducted with an inexpensive measuring system in which thermal stress applied to the DUT is small and thus measurement error caused by characteristic change of the DUT is less. A constant current smaller than the breakdown current of the DUT is applied to a DUT using a constant current source, and waveforms between terminals of said DUT are observed by a waveform observation device, thereby measuring the trigger voltage and the latchback voltage. When a constant current I is applied to the DUT from the constant current source, a stray capacitance C between terminals of said DUT is charged. Thus, the voltage between terminals of said DUT is increased with a constant inclination (I/C) as time goes by.

Abstract: An apparatus for detecting the position of a charged particle in a duct pipe has a plurality of electrodes arranged in the duct pipe. Detection signals obtained in the electrodes are phase-delayed by predetermined amounts and then added to form an integral detection signal. The integral detection signal is input to a circuit which determines waveforms representative of the passage of the charged particle: namely, the D.C. component of the detection signal, fundamental wave component and a phase-shifted fundamental wave component. The position of the charged particle are determined from these components. A part of each electrode is formed of a dielectric member. Each electrode and an associated connector are covered by a double-shield structure with inner and outer shields, the electrode, the connector and the inner shield being electrically insulated from the duct pipe.

Abstract: A method for comparing the quality of RF absorbers uses a TEM cell which is provided with a low-reflection termination, in which cell the absorber wall (5) is equipped with reference absorbers (13). A steep-edged pulse wave is radiated in by means of a pulse generator (9) and a scattered wave reflected by the test absorber (14) is detected by means of a sensor (10). A reflection of the absorber wall is then determined by means of a first calibration measurement. The reference absorber is removed in a test area and a reflection of a metal wall (8) lying behind it is then determined by means of a second calibration measurement. Finally, a reflection of the test absorber (14) arranged in the test area is determined in a comparison measurement.

Abstract: An arrangement for monitoring a transducer, or detector, which produces an analogue or digital output signal corresponding to a state sensed by the transducer. The invention is characterized in that the transducer includes activatable and deactivatable elements (RB 3, 23) which are intended to influence the transducer in a manner to cause the transducer to produce a signal which deviates from the actual state detected by the transducer, and in that there is provided a control circuit (10) which is intended to activate and/or deactivate the elements in a predetermined sequence, in response to the signal produced by the transducer. The arrangement also includes a control device for detecting the transducer output signal and comparing changes in the output signal in dependence on the activation and/or deactivation of the elements (RB 3, 23). The control device is constructed to detect whether or not the function of the transducer is correct, on the basis of this comparison.

Abstract: Capacitive-type measuring apparatus for making absolute measurements comprises first and second support members which are relatively displaceable with respect to a measurement axis; an array of first electrodes disposed on the first support member; an array of second electrodes disposed on the second support member such that differing portions of the second electrode array are capacitively coupled with the first electrode array in dependence on the relative positions of the support members; an array of third electrodes disposed on the second support member so as to be electrically connected to corresponding second electrodes and spatially offset therfrom by an amount which varies according to the position of the third electrodes from a reference position; and a fourth electrode arrangement disposed on the first support member for providing in combination with the other arrays a plurality of discrete signal transmission paths each having a capacitive transfer function with two components, one of which varies a

Abstract: A phase discrimination type electrostatic capacity detector includes an one-side electrode plate composed of a transmitting electrode and a receiving electrode, another-side electrode plate having coupling electrodes and disposed relatively movably with respect to the one-side electrode plate in a confronting relation with the same, a power supply connected to the transmitting electrode, and a detector circuit connected to the receiving electrode. The detector is miniaturized by disposing the transmitting electrode in a second hierarchy layer partitioned by an electrical insulating layer on a substrate and connecting in series the respective transmitting electrode elements of the same phase in a first hierarchy layer through coupling leads. The detector including a pair of receiving electrode elements between which the transmitting element is interposed, is miniaturized by leading out the coupling leads to one side end of the one-side electrode plate through a space between both receiving electrode elements.

Abstract: A non-contacting potentiometer includes a resistor and a movable probe which capacitively couples AC signals applied to the resistor to an output terminal. A closed loop control circuit is coupled to the resistor and the probe to compensate for variations in gap spacing between the probe and resistor.

Abstract: A method for detection of alien matter content in gas, in which the gas and the materials contained in it are ionized in an ionization room (1). The present methods are inaccurate and unreliable. The invention is based on a method, in which the ionized gas is led through chambers (2) containing different electric fields, out of which at least from one of the chambers the field current is measured, from which a signal is obtained, which describes the existence of alien matters in the gas. More parameters are obtained for detection of different materials by measuring favorably the currents passed through several electric field chambers as well as possibly by branching off from the ionization source the flow to different analysis lines of the electric field chambers.

Abstract: A detector (42) is provided for testing a string of lamps (12) that are connected to a wire (14) in a series configuration. The detector (42) has a probe (44) disposed on the end thereof with a cavity (56) formed therein. The cavity (56) is operable to be disposed around the socket (30) of lamp (12). The electrodes (34) and (36) disposed in the interior of the socket (30) are disposed parallel to two electrodes (60) and (62) that are embedded in the probe (44). A detector circuit is provided for detecting the presence of an AC signal capacitively coupled from one of the electrodes (34) and (36) to one of the capacitive plates (60) and (62), respectively. A large DC signal will be present for a defective bulb having at least one of the electrodes (34) or (36) connected to one side of an AC supply (18).

Abstract: Apparatus for measuring the total internal resistance of a multicell battery having positive and negative terminals employs a first transistor device having an input and an output and having mutually exclusive conductive and non-conductive electric states. An arrangement of resistances is connected in series with the device to form a network. The network is connected between the positive and negative terminals. An operational amplifier has an output connected to the input of the device and first and second inputs. The first input is connected to the network at a point connected to both of the device and the arrangement. A square wave signal alternating between a positive voltage and ground on alternate half cycles is applied to the second input. The device is in the conductive state when the alternating voltage is positive and is in the non-conductive state when the alternating voltage is at ground.

Abstract: A probe developing an admittance with a material whose condition is to be continuously measured is capacitively coupled with a variable frequency oscillator, preferably one having a digital output stage, for generating a variable frequency signal having a period varying with the admittance developed at the probe. Both the oscillator input and output are capacitively coupled to the probe. In a preferred embodiment, a set point circuit including a plurality of resistors coupled in parallel with the oscillator output and a plurality of switches coupled in parallel with the probe conductor and each with a different one of the resistor, provides easy circuit adjustment for use of the system with a variety of materials. A preferred digital circuit employing a pair of flip flops, fixed timer and one shot generate a fixed period variable duration duty cycle digital voltage level signal for transmission, if desired, or for conversion into a variable current signal.

Abstract: An optical fiber magnetometer having omnidirectional capability is disclo herein for measuring a total magnetic field independent of its physical orientation or the direction of the field or fields. A relatively long optical fiber defining a sensing arm for exposure to a magnetic field is wound in the form of a spheroid (like rubber bands on a golf ball or yarn threads on a baseball) to provide optical path lengths of substantially the same total length in every direction through the spheroid winding. The plane of polarization of light transmitted through the optical fiber winding is caused to rotate (Faraday effect) when the fiber or components thereof is exposed parallel to a magnetic field. The extent of plane rotation is determined, inter alia, by the total magnetic field passing through the spheroid winding.

Abstract: A capacitive difference sensor includes two sensor electrodes, each of which lies opposite a transmitting electrode fed by an electrical AC voltage source. A circuit arrangment connected to the two sensor electrodes for signal recovery generates a differential signal which corresponds to the difference between the displacement currents induced in the two sensor electrodes. The circuit arrangement includes a series resonance circuit comprising a coil and a capacitor, the resonance frequency of the series resonance circuit corresponding to the frequency of the AC voltage source. The two sensor electrodes are coupled via a transformer in opposite senses to the series resonance circuit and the differential signal is tapped off at the tap of the series resistance circuit formed by the connecting point between the coil and the capacitor.

Abstract: Apparatus for indicating a predisposition to kidney stone disease in humans, and also dehydration, and for monitoring the efficacy of hydration therapy, comprises a conductivity probe including a tip which can be inserted into urine so that a drop thereof adheres to the tip, and display means for indicating the result as a derived function of conductivity (electrolyte concentration) in terms of urine specific gravity or osmolality. Preferably the probe electrodes are small and are spaced closely together so that the streamlines between the electrode tips are such that maximum current flows substantially within the adherent drop of urine.

Abstract: A monitoring circuit for a battery charger, with utility in other applications, includes a main input that receives an initial signal such as the terminal voltage of a battery being charged, and a two-stage comparator, each stage preferably an operational amplifier. The initial signal is applied to the inverting input of the first stage, which is a differencing amplifier that also serves as a gain block; the initial signal is also delayed a brief interval, typically more than a second, and then applied to the non-inverting input of the first stage of the comparator. The inverting input of the second stage of the comparator receives the same signal as the non-inverting input to the first stage, whereas the non-inverting input to the second stage is derived from the output of the first stage.

Abstract: A procedure and a device for determining corrosion of preferably insulated structural parts (2) assures in a simple way early detection of corrosion. For this purpose an electric conducting resistance wire (4) exposed to the same corrosive medium, e.g. condensation water, as the structural part (2) to be examined for corrosion is placed outside the structural part (2) and the electrical resistance of the resistance wire is measured. The effective cross-section of the resistance wire (4) and its electrical resistance change with the corrosion of the resistance wire (4) so that the resistance change of the resistance wire (4) registers the effect of the corrosive medium.

Abstract: In a switchable impedance tester for measuring very small impedances, the effect of switch impedances is eliminated by connecting the test load between two switching transistors in their emitter-collector circuit, and driving them with operational amplifiers arranged to urge their inputs into equality. A test voltage source is connected across first inputs of the amplifiers, and the other inputs are connected between the respective transistors and the load. This produces an operational condition in which the voltage across the load is independent of the parameters of the switching transistors, i.e. the switching transistors appear to have zero impedance.