Abstract: The device for monitoring the operating parameters of a dynamic system (for example, an aircraft having an internal combustion engine power plant) comprises a plurality of sensors each one of which is adapted to measure the magnitude of a specific operating parameter and to generate a sensor signal voltage that varies directly with the magnitude of the operating parameter. The sensor signal voltage generated by each sensor is transformed to a conditioned and calibrated analog signal voltage the magnitude of which is in the same proportion to a predetermined reference voltage as the actual magnitude of the operating parameter being measured is to a predetermined reference magnitude of the operating parameters. The conditioned analog signal voltage gradient is divided into a predetermined number incrementally increasing analog signal voltage increments, and analog signal voltage increment indicator means are provided for visually indicating the analog signal increment that corresponds to the actual magnitude of the operating parameter being measured. Selector switch means are provided for selecting the conditioned analog signal that corresponds to a particular one of the operating parameters being measured. The selected conditioned analog signal is converted to a corresponding multibit digital signal which is transmitted to an array of alpha-numeric visual display units which display in numeric form the actual magnitude of the particular operating parameter being measured.

Abstract: A control circuit for turning off the power to the pump drive motor when the pump has exhausted the supply of liquid in the well. Means for sensing the instantaneous current to the pump motor and a circuit measuring the average current drawn by the pump drive motor, and turning off the power when the average current decreases below a preset level. An RC circuit having a time constant greater than the time required for the pump to complete one full pumping cycle for measuring the average current to the motor, and a comparator controlling switching means to shut off the power when the average current to the motor decreases to a predetermined amount. A reference voltage supplied to the comparator from an amplifier connected to the electrical power in which the output of the amplifier varies inversely to variations of the voltage of the electrical power thereby preventing fluctuations in the supply voltage from adversely affecting the control circuit.

Abstract: The output power level of a laser is stabilized at a predetermined set point by a feedback control circuit. The light emitted from one end of a laser is detected and converted into an electrical current by a photodetector. This current is then amplified and converted into a proportional voltage by a buffer amplifier and the resultant voltage is compared to a reference voltage to provide an error signal. The error signal is integrated and fed back to correctively adjust the driving current for the laser, thereby compensating for any tendency of the power level of the light beam emitted from the other end of the laser to drift from a predetermined set point.

Abstract: A DC power supply circuit of the switching or chopping type for converting a voltage from an AC power source or from a DC power source into a predetermined DC voltage and supplying the converted DC voltage to a load, comprises a converting transformer having first and second primary windings and a secondary winding and first and second switching circuits connected to the first and second primary windings, respectively, and being selectively operated for switching or chopping the voltage applied from the AC or DC power source to the respective primary winding thereby to produce a pulse voltage at the secondary winding of the converting transformer to which a rectifier circuit is connected. The converted DC voltage obtained at the output of the rectifier circuit is connected. The converted DC voltage obtained at the output of the rectifier circuit is compared with a reference voltage, and the switching circuits are controlled on the basis of such comparison for maintaining the converted DC voltage at a predetermined level.

Abstract: A circuit for generating a waveform comprising a train of rectangular pulses in response to a train of trigger signals such that the duration of each rectangular pulse is a precise multiple of the time lapse between pulses, in spite of variation in the waveform''s absolute period. The circuit employs a flip-flop set by a trigger signal and timed to reset by a ramp signal-toreference voltage comparison circuit. The output of the flip-flop is subject to continuous adjustment by the circuit to achieve the desired waveform, and to this end is monitored by a first discharging current source producing a fixed current and activated by the set state and a second charging current source producing a fixed multiple, the desired time lapse multiple, of the first current and activated by the reset state. Should one of the current sources be kept on too long by a deviation of the relative pulse (set) and lapse (reset) durations from the desired multiple, a capacitor driven by the two sources will be relatively over-or undercharged, depending on which current source is overactivated, and the charge and hence voltage change will be monitored to adjust the reference voltage to return to the desired timing multiple.

Abstract: A storage capacitor, periodically charged through a chopping transistor via an inductance which during cutoff of the transistor maintains the flow of charging current by way of a diode, energizes an output terminal through a d-c/a-c converter, a transformer and a rectifier in tandem therewith. A sensor responsive to the voltage (or current) on that terminal feeds one input of an analog-type first differential amplifier whose other input receives a constant reference voltage (or current) and whose output constitutes an error signal. A binary-type second differential amplifier compares this error signal with the output of a sawtooth-wave generator and, on detecting a coincidence therebetween, energizes a differentiation circuit which generates a turn-on pulse for the switching transistor; a turn-off pulse for that transistor is periodically produced by a gating circuit which also triggers the sawtooth-wave generator. Two pulse transformers galvanically separate the gating circuit and the switching transistor from the sawtooth-voltage generator and the associated amplifier and differentiation circuit.

Abstract: An automatic power-on reset circuit adapted for use on complementary MOS integrated circuit semiconductor dies is provided. The circuit includes a voltage reference stage followed by an amplifier stage. A PN diode is coupled in series with a diode-connected MOSFET and a low current MOSFET device to provide a slight overdrive to the P-channel MOSFET of a CMOS inverter, which determines the initial output level thereof. As the voltage applied to the power supply conductor increases, the switching point of the amplifier-inverter stage varies until the output thereof assumes the opposite logic level. This transition of the output of the amplifier inverter stage is applied to wave shaping circuitry and an output circuit which reliably produces the desired reset signal.

Abstract: A liquid level sensing device intended to sense the level of oil in an engine crank case with means for filling the case with oil from a reserve tank if the oil level is below a desired level. The sensing device is a thermistor having a negative coefficient of resistance. It is wired to a bridge circuit containing a Zener diode for a voltage reference. The circuit is operated by a manual push button and an SCR made conductive. If the oil level is below the desired level, a solenoid valve opens a conduit to a reserve tank and the crank case is automatically filled.

Abstract: An efficient d-c to d-c converter power supply has over-voltage protection, the over-voltage protection circuitry being particularly applicable for use with power supplies having high current output characteristics. A reference voltage detecting device is connected to the high voltage load line as well as the control terminal of a thyristor device which is connected in series with a resistor across the load terminals so that when an over-voltage condition exists, the thyristor device is triggered into conduction, developing a voltage across the resistor which is applied to a circuit isolating device which has its output operably connected to the oscillator and shuts off the oscillator and power supply. Supplementary over-voltage protection circuits are included to provide protection against multiple failure of various components or portions of the circuitry.

Abstract: A power supply system comprising a plurality of parallel connected voltage regulators, each regulator having a voltage control loop. Each voltage regulator is provided with a circuit which increases the reference voltage supplied to the voltage control loop so that the control loop of each regulator is prevented from being cut off during standby operation.

Abstract: A battery charger is equipped with a current adjusting device. A current sensor continuously measures the current output from the charger and feeds the readings to a current comparator. The terminal voltage of the battery is also continuously read and the readings are fed to a voltage comparator. A voltage reference feeds a constant reference voltage to the voltage comparator. The voltage comparator compares the battery voltage with the reference voltage and feeds a signal dependent upon the voltage difference and in accordance with a preselected program to a current reference. The current reference delivers a signal dependent on the output of the voltage comparator and in accordance with a preselected program to the current comparator. The current comparator to the the signal received from the current sensor tothe signal received from the current reference and provides an output signal to cause the current adjusting device to adjust the charging current to the values called for by the preselected program. A typical charge program which can be selected is a first charging mode at the initial charge rate of the battery until the battery voltage rises to a preselected value slightly below the gassing voltage. This is followed by a second charging mode wherein the charging current is gradually diminished so as to hold the voltage constant at the preselected value. When the charging current drops down to the finishing rate of the battery, a third mode commences wherein the current is held at the finishing rate regardless of further increase of the battery voltage. The charge can be terminated by a timing device set for total charge time or alternately for a predetermined charge period at the finishing rate.

Abstract: A portable battery-operated fluorescent light with an inverter having a single transistor Class C oscillator and a gapped-core nonsaturating reactor transformer with a parallel capacitance in the secondary circuit to cause the secondary circuit to act as a resonant tank circuit for the oscillator. The lamp is capacitor-ballasted, and the batteries are rechargeable. A large capacitance is connected in parallel with the batteries to decrease effective battery impedance. The light has an automatic shutoff circuit using a zener diode to shut off the inverter when the batteries are discharged to the safe limit and a self-contained constant voltage current-taper charging circuit for the cells, with the same zener diode as a voltage reference. A jam-in lamp socket is shown which allow the lamp to be inserted straight into the socket without rotation, and a method for pulsing the filament at one end of the lamp to improve startup of aging lamps is disclosed.

Abstract: A circuit for use in a bar code reader or similar device for establishing a reference voltage which is used by the reader to distinguish different types of bars. In operation, the reader scans the individual character bits in the code and provides a reader scan signal, the voltage level of the scan signal depending on the amount of light reflected from the particular character bit being scanned. The reader scan signal typically comprises alternating series of positive and negative peaks, each positive peak representing a white area or space (one type of character bit), and each negative peak representing a black area or bar (another type of character bit). A fast charge-slow discharge circuit responsive to the reader scan signal establishes a fast peak signal generally at the level of the successive positive peaks of the reader scan signal, and a slow charge-fast discharge circuit responsive to the reader scan signal establishes a second peak signal generally at the level of the negative peaks of the reader scan signal. These two peak signals are coupled to opposite ends of a large value of resistance, and the reference voltage signal is established at the approximate midpoint of the resistance. The value of the reference voltage signal thus is approximately midway between the value of the two peak signals. This reference voltage is then compared with the reader scan signal, and an identification signal having two levels is obtained thereby, one level of the identification signal indicating a black bar, when the reader output signal is greater than the reference voltage signal, and the other level indicating a white bar or space, when the reader scan signal is smaller than the reference voltage signal.

Abstract: A fractional part of a voltage to be regulated is applied between the base electrodes of first and second emitter-coupled transistors having base-emitter junctions with different VBE versus current characteristics. The collector currents of the first and the second transistors are caused to be in a predetermined ratio by a degenerative feedback loop which adjusts the value of the voltage to be regulated. Since the aforesaid fractional part of this voltage must vary linearly with the temperature change of the first and second transistors in order to maintain their collector currents equal, the voltage to be regulated must vary inversely as this fraction with that temperature change. The fractional part can be of fixed value, in which case the voltage to be regulated will vary linearly with the temperature change of the first and second transistors, or it can be changed from one value to another to cause the voltage to be regulated to vary in a more complex manner with temperature.

Abstract: Heating indicating device for the rotor of an electric motor notably using direct current. According to the invention, this device is characterized in that it comprises a resistor mounted in series with said rotor, means reading the voltage across said resistor and supplying an output voltage corresponding to the square of the input voltage, means simulating the thermal exchange time constant between said rotor and its environment and causing progression, in time, of said output voltage in accordance with said time constant, means for emitting a reference voltage representative of the maximum allowable temperature that must not be exceeded for the rotor and means for comparing this reference voltage and the output voltage of the means simulating the time constant. Supervision of motor, notably in printing machines.

Abstract: A PUT circuit compares a zener reference voltage with the voltage of an electronic flash storage capacitor, and starts and stops a battery powered d.c. to d.c. converter oscillator, which charges the capacitor, as necessary to maintain the capacitor voltage within desired limits. A zener diode in the PUT cathode circuit provides the desired hysteresis. A second PUT circuit compares a second zener reference voltage with the battery voltage, and stops the oscillator when the battery voltage drops to a predetermined minimum value.

Abstract: There is disclosed herein a VSWR alarm system which produces an alarm when an undesired VSWR is present on a transmission line. The alarm system includes a directional coupler to detect the forward voltage and reflected voltage on the transmission line. An amplifier amplifies the reflected voltage by a given value dependent upon the desired VSWR. An amplitude comparator employs the amplitude of the forward voltage as a reference voltage and compares the amplitude of the amplified reflected voltage to this reference voltage. When the amplitude of the amplified reflected voltage is greater than the amplitude of the reference voltage, an alarm indication is produced. The production of the alarm indication can only produce an alarm when there is transmitting energy on the transmission line due to a NAND gate coupled to a transmitter logic circuitry and the amplitude comparator. A storage device is coupled to the output of the NAND gate and provides a VSWR alarm when the alarm indication is present in the storage device. A fault lamp is activated and an alarm is produced when the storage device stores the alarm indication. A timing circuit responsive to the activation of the fault lamp is employed to reset the storage means after a given time interval.

Abstract: A protection circuit for a transmitter amplifier is provided which senses the forward power level and develops a first voltage which is compared with a reference voltage to provide a control voltage which controls the power developed by the transmitter amplifier. An increase in the forward power level is detected changing the control voltage to cause a reduction in the forward power developed by the transmitter amplifier. A decrease in forward power level is detected changing the control voltage to cause an increase in forward power developed by the transmitter amplifier. A forward power level below a predetermined level for a predetermined period of time is detected causing a reduction in the reference voltage. Reduction of the reference voltage reduces the control voltage to reduce or terminate the forward power of the transmitter amplifier. An excessive control voltage coupled to the transmitter amplifier is also detected increasing the first voltage which in turn causes a reduction in the control voltage thereby maintaining the control voltage below a preset level.

Abstract: Device for regulating the voltage of an electric energy source constituted of a group of solar cells gathered into modules. Each module have one terminal connected to a common conductor and an other terminal connected through a diode to a distribution conductor. The device comprises electronic interrupters connected between the common conductor and the terminal of a module connected to the diode, so as to short-circuit the module. A proportional shunt is connected between a point at the distribution conductor potential and the common conductor. A differential amplifier is provided between the distribution conductor and a reference voltage generating device. An analogdigital converter the input of which is connected to the output of the differential amplifier and a part of the outputs of which control the electronic interrupters, the remaining outputs controlling the proportional shunt.

Abstract: A battery charger comprises a variable current DC power supply adapted to be connected across a secondary battery, an AC modulator connected to the DC power supply, a phase sensitive detector adapted for connection across the battery, AC voltage reference signal means connected to the phase sensitive detector, and means for monitoring the amplitudes of two different voltage components of the AC voltage appearing across the battery. An impedance controlled battery charger is described in which the monitoring means of the above type of battery charger are provided in the form of a feedback control connected from the output of the phase sensitive detector to the DC power supply automatically adjusting DC current to match current accepting capabilities of the battery. Methods of battery charging are also described.

Abstract: A voltage and temperature stable integrated voltage regulator circuit offsets the negative temperature coefficient of the baseto-emitter voltage of one transistor with a positive temperature coefficient derived from the base-to-emitter voltage differential Delta VBE between a pair of additional transistors Other transistors are used to produce a pair of regulated stable output voltages, each having a predetermined voltage with respect to a different one of the two input voltage terminals across which the regulator circuit is connected Circuit components are provided to cause the two output voltages to be voltage and temperature stable or to have a predetermined controllable temperature coefficient

Abstract: A monolithic 10-b plus sign D/A converter has been developed that incorporates all necessary circuit functions including voltage reference and internally compensated high-speed output op amp in a single 82/spl times/148 mil chip. A unique logic switch and current source configuration achieves 0.05 percent nonlinearity with /spl plusmn/10 V compliance current output option as well as true or complementary binary coding. The design constraints and area requirements for scaling of current source emitter areas are reduced by using a new active current-splitting technique. The circuit features a 1.5 /spl mu/s settling time voltage output and sign-magnitude coding.

Abstract: A battery charger for charging a temperature-sensitive battery in a rapid manner without damage to the battery, such batery being equipped with means for providing a reference voltage whose level changes with battery temperature in a similar fashion to the theoretical battery voltage change with temperature. The battery charger comprises a current-carrying conductor adapted to be connected to one terminal of the battery to be charged, with the conductor including a controlled current limiting switch serving to diminish the average amount of current flowing into the battery at such time as the battery has become patially charged. Means are provided for recurringly turning said switch on and off so as to produce a sawtooth waveform, and means sensitive to the comparison of the reference voltage with the actual battery voltage are arranged to cause a diminishment of the average value of the sawtooth waveform, thus to prevent damage to the batery from heating or from overcharging. The means for providing the reference voltage may be silicon diodes disposed in the battery case, and the diminishment of current may be brought about by causing a decrease in the amplitude of the sawtooth waveform, by causing a spreading of the peaks of the sawtooth waveform, or by the use of both of these techniques.

Abstract: An analog-to-digital converter for converting at a high rate an analog input signal into a digital signal by comparing it with a predetermined reference voltage parallelly. The converter comprises a plurality of parallel-connected comparators having window type comparison characteristics and each of which produces a binary-code signal of "1" or "0" only when the analog input signal is at a value within a window, that is, between a couple of reference voltages predetermined for respective comparators, and a code converter for converting the parallel output signals from the comparators into a series of binary-code signals having a predetermined number of bits.

Abstract: A surge tester simultaneously applies oppositely polarized surge pulses to a test winding and a standard winding. If there is an unbalance in the electrical characteristics of the two windings, a difference voltage representative of the difference in the voltages developed across the windings is applied to a fault detecting circuit. If the unbalance is sufficiently great, a fault indication is provided. A fault indicator circuit includes an electronic control device arranged so that it can be gated into a conductive condition in response to a fault condition only during half cycles of line voltage of one polarity and the surge pulses are applied to the windings only during half cycles of the opposite polarity. The magnitude of the difference voltage, representative of an unbalance condition, is compared against a reference voltage which varies in accordance with fluctuations in the line voltage. A ground fault condition is represented by an oscillatory voltage and this is detected by providing a fault indication only if the number of pulsations of the oscillatory voltage attains a given pulse count within a given period of time.

Abstract: Apparatus for phase shifting between radiating elements of an antenna array by utilizing the inherent phase difference existing between frequency locked oscillators. Power from a master oscillator is injected into a plurality of slave oscillators, each of which feeds a different radiating element. The slave output is also fed through a directional coupler into a phase comparator which receives a comparison output signal from the master oscillator. The comparator output and a DC phase reference voltage are applied to a differential amplifier whose output forces the free-running frequency of the slave oscillator to change until the comparator output equals phase reference voltage.

Abstract: A precision temperature controller utilizing a temperature sensitive resistive element in thermal relationship to an object to be heated, the element being connected in a bridge circuit to derive an error signal proportional to deviation from a desired temperature, the error signal being summed with a sawtooth voltage, the output so obtained being compared with a reference voltage in an operational amplifier to derive a pulsed output having a pulse width proportional to the error signal, the pulse width being used to control the time duration of energization of a heating element in proximity to the resistive element.

Abstract: A logarithmic amplification circuit which includes a logarithmic transfer circuit which produces a video output voltage which is a logarithmic function of a video input voltage and which also includes a feedback circuit which samples the video output voltage during the horizontal blanking interval, compares the sampled voltage to a reference voltage and develops an error correction signal which is fed back to the input of the logarithmic transfer circuit and which is applied during the horizontal blanking interval to correct the black level of the video input signal. The logarithmic transfer circuit includes a bipolar transistor connected in the common emitter configuration and a field effect transistor having its gate and source respectively connected to the collector and base of the bipolar transistor. A current source converts a video input voltage to a corresponding video input current which is applied to the logarithmic transfer circuit. The feedback circuit includes a field effect transistor which is gated on during the horizontal blanking interval to sample the black level of the video output signal; a capacitor which stores the sampled voltage; a differential amplifier which compares the sampled voltage with a reference voltage and develops an error correction signal which is stored on a black level storage capacitor; and a field effect transistor which is gated during the horizontal blanking interval to clamp the black level of the video input voltage to the level on the black level storage capacitor.