Abstract: The disclosure describes improved apparatus for driving a load, such as a meter, in proportion to a source voltage produced by a signal generator. The apparatus includes a non-differential gain stage for generating an amplified voltage between a gain stage output and one of the generator outputs. The non-differential gain stage is followed by a differential stage which generates a rereferenced voltage between the differential stage output and one of the load terminals. The rereferenced voltage is proportional to the amplified voltage and is substantially independent of any offset voltage between the one generator output and the one load terminal. By coupling the rereferenced voltage to the load, the load voltage is made proportional to the source voltage irrespective of changes in the offset voltage between the one generator output and the one load terminal. The load may include a meter and an amplifying stage for ranging and zeroing the meter.

Abstract: A single wire microelectrometer imaging system is disclosed wherein a latent electrostatic image charge pattern is produced, then measured from point to point across the charged image surface and then transmitted for processing if desired. It is found that this system provides multiple image information from a single exposure which is especially significant in xeroradiographic medical diagnostic imaging processes. Thus instead of developing a latent electrostatic image which is produced the charge is captured and transmitted, to be stored or further processed if desired. The captured image may be shown in either hard copy form or on a video screen as desired.

Abstract: The output voltages produced by two directional couplers are applied to analog circuitry for generating a voltage that is directly proportional to return loss. An analog meter scale is calibrated to indicate return loss in decibel units and/or voltage standing wave ratio (VSWR) directly.

Abstract: An electrometric apparatus, which uses a measuring device that provides a high impedance dc signal which varies in accordance with the variable to be measured. The dc signal is amplified by at least one amplifier means and the amplified signal is applied to an indicating means which indicates the amplitude of the amplified dc signal. The supply voltage for the amplifier means is provided by a dc power supply means connected through a regulating means to positive and negative supply busses and for the amplifier means. The regulating means includes a transistor having its emitter-collector circuit connected in series between the power supply means and the positive supply bus of the amplifier means. A resistor and a Zener diode are connected in series and the series combination is shunt connected between the supply busses. A pair of series connected resistors are shunt connected between the supply busses.

Abstract: Two differential amplifiers are provided each having two input terminals. One of the input terminals of each differential amplifier receives an output signal derived from a measuring circuit, while the other terminals of the differential amplifiers are coupled to each other. Output signals of the respective differential amplifiers control correspondingly two series-connected current control circuits, respectively. With such a circuit arrangement, a current flowing through a receiving unit connected in series to the two current control circuit is controlled in response to the output signal from the measuring circuit.

Abstract: A device for accurately measuring the quantative value of the real part of complex impedance without the measurement affecting or being affected by the reactive component of that impedance. The device is useful for impedance matching, and especially for tuning antennaes and the like such that the real part of the impedance can be appropriately matched with the source or receiver during tuning. The device operates by comparing the power delivered to the load with the power dissipated in a resistance R when a current proportional to the main line current passes through it. When both power readings are the same, which may be determined by a null indicator, the real part of the load impedance equals the resistance R.

Abstract: An electrical testing instrument including an amplifier circuit having a pair of inputs, one comprising a probe and the other being adapted for manual engagement by the user for completing an input circuit through the body of the user. The circuit has a battery and a current-responsive indicator in its output circuit to provide a signal when current flows in the input circuit to provide a critical forward biasing of the amplifier. The battery is connected to furnish such input current when the input terminals are connected in a closed circuit having a resistance of at least approximately the resistance of the user's body. The amplifier circuit is further arranged that when the probe is contacted with a live AC power line and the manually engageable input terminal is so manually engaged, an operating indicating current will also be present in the output circuit.

Abstract: It has been determined that unique discharge signature waveform shapes are associated with the corona discharges in the components of the power separation filters of repeaters and equalizers. These signature waveform shapes, present across the repeater or equalizer terminals, can be measured and identified by artificially contaminating and inducing corona discharges in the high voltage components. A discharge signal subsequently generated in response to a corona discharge across a high voltage component of a repeater or equalizer of a similar type will have the same shape as one of the signature waveforms. Thus, a corona discharge from a repeater or equalizer under test can be located by comparing its discharge signal with the catalog of signature waveforms.

Abstract: An arrangement for the determination of the effective value and/or the performance or power and, for example, also the cross-power of electrical signals, in particular those Doppler signals which are received in ultrasonic-Doppler blood flow measurement. The arrangement includes an amplifier for the present electrical signal regulatable in amplification which, on the one hand, is connected into a control loop or circuit for regulating the degree of amplification for the purpose of producing constant amplifier power outputs and, on the other hand, connected into a measuring circuit for determination of the degree of amplification which adjust itself at the current power constant-regulation of the amplifier.

Abstract: A watt/watthour meter of improved accuracy and relatively lower cost than a conventionally designed device with similar specifications. A current proportional to instantaneous power is obtained from a current-voltage multiplier circuit and is maintained as a current signal through amplifying and filtering, and through the watt output load. The watt output amplifier is a current input, current output amplifier which simultaneously functions as an active ripple filter. It directly couples the input signal to the inverting input and capacitively couples the input ripple to the non-inverting input of the amplifier's op-amp. The output load, which is externally connected between the inverting input and the output of the op-amp, does not have a common with the internal ground and effectively floats with the ripple.

Abstract: Shunt means supply a diode bridge with an alternating current proportional to the AC to be measured. The bridge has at least two electroluminescent diodes which emit two alternating streams of half-wave light pulses which are supplied to two fibre optic systems. These convey the light signals to a safe distance from the high tension line where two light receptors receive the respective streams of half-wave light pulses and apply electrical signals proportional thereto to opposite inputs of a differential amplifier. The output of the amplifier is a readily measurable AC. Balancing means may be provided to compensate for any difference in the overall transmission paths for the two half-wave pulse streams. A resistive load may be provided adjacent the line to sink the current flowing through the diode bridge.

Abstract: A range switching circuit for a solid state electrometer, e.g., for use in radiacmeter, includes a substantially symmetrical circuit having an n-channel MOSFET and an NPN transistor in one branch and a p-channel MOSFET and a PNP transistor in the other branch. The electrometer includes an operational amplifier with two high value resistors in the feedback path. A latching reed relay selectively shorts out one of the feedback resistors when one of the transistors is gated on by the corresponding MOSFET.

Abstract: An electrical quantity measuring device is disclosed that includes a probe unit presenting high impedance, which device is suitable for measuring voltage. The components of the measuring device, except for the probe unit, are housed in a cabinet having a meter mounted thereon for external viewing. The probe unit has a contactor and provides an output signal indicative of the predetermined quantity of an element to be measured during contact of the element with the contactor and a ground lead. A high impedance between the contactor and the probe output is provided by a plurality of field effect transistors, and an operational amplifier, the gate of the first of which transistors is connected with the contactor and the gate of the second of which receives a feedback signal from the processing circuitry of the measuring device within the cabinet. A third field effect transistor is connected with the first field effect transistor and compensates for leakage current.

Abstract: The apparatus is intended for measuring the moisture content of moving dielectric materials. The apparatus comprises an aerial adapted to directly receive electromagnetic radiation signals caused by static electric discharges occurring at each moment of time between production apparatus and a moving dielectric material, the signals carrying information about the moisture content of the material. The aerial is connected to a bandpass tuned filter, a detector, an inverter and a recording device, all of which are connected in series. The apparatus may be provided with one or two comparators to prevent the occurrence of a false signal when the moving material breaks up and to register overloading of the device.

Abstract: A circuit permitting an operator to accurately calibrate an instrument to indicate when a variable analog quantity being measured is zero. The analog signal is connected to the input of an operational amplifier which operates in stable mode for large analog inputs and operates in oscillation mode for very small analog inputs. The output of the operational amplifier is compared to zero and when the analog input is greater than zero, the comparator output is a logic zero. When the analog input is less than zero and not in the immediate vicinity of zero, the comparator output is a logic one. When the analog input is very small and less than zero, the operational amplifier operates in oscillation mode as the circuitry connected thereto causes it to oscillate with the duty cycle of the negative portion of the oscillation decreasing as the analog input comes closer to zero. Accordingly, the output of the comparator also oscillates.

Abstract: The bases of a first pair of opposite conductivity transistors are connected to one input terminal of the amplifier circuit. A conventional meter is connected in the collector-emitter path of a second pair of transistors. Four arrangements are disclosed for coupling the first pair of transistors to the second pair; two of the embodiments enable DC signals to be measured and the other two AC signals.

Abstract: For measuring the load current in a static convertor, there are provided a direct current measuring device on the direct current side of the convertor and an alternating current measuring device on the alternating current side. These measuring devices are connected by a dominance coupling arrangement to the output side of the measuring device. There the signal is fed to a control pulse transducer, which controls the convertor in accordance with the greatest of the signals fed by the measuring device.

Abstract: A high impedance voltage probe with excellent high frequency response and extremely light loading of the circuit under test. The probe uses an IGFET input device having its source connected to a constant current source and to an amplifying device, and its drain connected to a variable voltage source. The output of the amplifying device is connected to a constant current source, to a non-linear voltage translating device and to an output terminal. The voltage translating device is also connected to the variable current source.

Abstract: A portable kilovoltmeter especially suited for measuring the secondary voltage of an ignition coil includes an operational amplifier whose input is connected via an input circuit to the ignition coil secondary winding and whose output is connected via an output circuit to a galvanometer on which the secondary voltage is read. The input circuit to the operational amplifier includes a probe which forms a portion of a capacitive voltage-dividing network via which the secondary voltage is reduced in amplitude before it is supplied to the operational amplifier input. The probe includes a capacitive probe element which makes contact with the hot terminal of the ignition coil secondary and a length of high-tension, high-resistance conductor which leads from the probe element to the console containing the galvanometer and the kilovoltmeter circuitry.

Abstract: Centralized telephone circuit testing equipment with receptacles for selectively receiving a wide variety of electronic circuit modules, various modules being provided to make the equipment capable of performing a large number of commonly employed telephone tests. A scanning system is disclosed as part of the central measuring equipment for determining which of a plurality of remote testing stations has requested access to the central measuring equipment, one requesting remote station at a time being given complete control over a test function of the central measuring equipment for conducting tests on a telephone trunk.

Abstract: A circuit for determining a measured value of a rectified a-c voltage of the type having at least one compensation diode for compensating the diode threshold values in the rectifier and which is connected in series therewith, in which the diode is connected in series with the same polarity as the rectifier diodes, a compensation resistor shunted by a voltage divider is connected in series with the compensation diode and an operational amplifier is connected in parallel to the diode and compensation resistor such that the desired compensation voltage always appears across the compensation resistor.

Abstract: Baseline drift and noise can produce difficulties in registering signals quantitatively without recourse to frequent rezeroing of the registering instrument. The invention provides a circuit in which the registering instrument only functions when a required signal is to be noted, the instrument at all other times being at a zero reading. The characteristics of a signal to be registered will be known. The circuit includes a differentiator which notes the rate of change of incoming signals and operates a switching device upon detecting a required rate of change to enable the signal to pass to the registering instrument. At all other times the registering instrument is isolated by the switching device.

Abstract: The combined current and voltage measuring apparatus has a cast resin body which supports the current measuring unit. The voltage measuring unit includes a capacitive voltage divider with an amplifier connected thereto. The cast resin body is also utilized as dielectric for the capacitor on the high-voltage side of the capacitive voltage divider. Embedded in the cast resin body is an auxiliary capacitor with a dielectric which, with respect to temperature dependence, corresponds to the dielectric of the high-voltage capacitor. The auxiliary capacitor, in series with a resistor, is connected to an auxiliary generator. The voltage dropped across the resistor is supplied, after rectification, to an input of a differential amplifier; the other input of the differential amplifier is connected to the terminal away from ground of the capacitor on the low-voltage side of the capacitive voltage divider.