Showing papers on "Voltage published in 1975"

Satellite Anomalies from Galactic Cosmic Rays

Abstract: Anomalies in communication satellite operation have been caused by the unexpected triggering of digital circuits. Interactions with galactic cosmic rays were investigated as a mechanism for a number of these events. The mechanism assumed was the charging of the base-emitter capacitance of sensitive transistors to the turn-on voltage. The calculation of the cosmic ray event rate required the determination of transistor parameters, charge collection efficiencies, and the number of sensitive transistors. The sensitive transistors were determined by analyzing the results of a scanning electron microscope experiment. Calculations with iron cosmic rays resulted in an event rate of 3.1 × 10-3 per transistor per year, in reasonable agreement with the observed rate of 1.5 × 10-3.

Voltage clamping with a single microelectrode.

Abstract: A technique is described which allows neurons to be voltage clamped with a single microelectrode, and the advantages of this circuit with respect to conventional bridge techniques are discussed. In this circuit, the single microelectrode is rapidly switched from a current passing to a recording mode. The circuitry consists of: (1) an electronic switch; (2) a high impedance, ultralow input capacity amplifier; (3) a sample-and-hold module; (4) conventional voltage clamping circuitry. The closed electronic switch allows current to flow through the electrode. The switch then opens, and the electrode is in a recording mode. The low input capacity of the preamplifier allows the artifact from the current pulse to rapidly abate, after which time the circuit samples the membrane potential. This cycle is repeated at rates up to 10 kHz. The voltage clamping amplifier senses the output of the sample-and-hold module and adjusts the current pulse amplitude to maintain the desired membrane potential. The system was evaluated in Aplysia neurons by inserting two microelectrodes into a cell. One electrode was used to clamp the cell and the other to independently monitor membrane potential at a remote location in the soma.

Method for determining battery state of charge by measuring A.C. electrical phase angle change

Abstract: Several embodiments for determining the state of charge of a cell or battery are disclosed. In accordance with one method of this invention, an A.C. voltage is applied to a cell or battery through a shunt. The phase angle between the A.C. voltage across the battery terminals and the A.C. current through the battery (measured as a shunt voltage) is continuously monitored. This phase angle is converted to an analog voltage which represents the A.C. component that is phase shifted by the impedance of the battery. The impedance and thus the phase angle changes with the state of charge of the battery. The analog voltage can be coupled to a meter that provides a phase angle reading or a state of charge reading. Further, the analog voltage can be used to control charge and discharge circuitry. In accordance with a second method, the state of charge of a battery is determined by taking phase angle readings based on input and output A.C. voltages.

Power supply system having two different types of batteries and current-limiting circuit for lower output battery

Abstract: A system constituted at a relatively large capacity and low output first battery such as a fuel cell, a smaller capacity and higher output second battery, and a current-limiting circuit for restricting the maximum discharge current of the first battery to a predetermined value slightly above the open-circuit voltage of the second battery, which circuit consists of a measuring circuit for measuring the discharge current, a signal generating circuit for providing a reference signal representing the predetermined current, a comparator for the comparison between the reference signal and the measured current and a current flow control circuit operated by the output of the comparator.

Apparatus for high voltage resistance measurement

Abstract: Improved method and apparatus for measuring the effective operating resistance of an unknown resistance element to which repetitive high voltage pulses are normally applied during operation. As each high voltage pulse is applied to the element, the voltage across the element and the current through the element are simultaneously sampled during voltage peak or at any other desired point in each pulse. The voltage and current samples are digitized and used in digitally computing the effective operating resistance of the unknown element. The computed resistance is displayed on a digital indicator.

Voltage regulator tester

Abstract: A test circuit for automotive voltage regulators includes means for simulating transient battery voltages, a meter for monitoring these voltages as related to the operation of the regulator being tested, switching means to protect the meter and also to facilitate the reading thereof, a test load simulating the field coil of an automotive alternator, and an indicator light for determining when the test load is energized. The volt meter indicator moves to show increasing voltage and returns to zero when the regulator interrupts the current to the test load.

Hot-carrier instability in IGFET's

Abstract: Injection of hot carriers from the channel region into the gate insulator of an IGFET imposes design constraints on the device dimensions and operating voltages. A fraction of the injected charge is trapped in the gate dielectric, and an undesirable shift in the operating characteristics results. The magnitude of the shift is related to the device dimensions, operating voltages, and gate dielectric.

Phase-locked loop circuit

Abstract: A phase locked loop circuit comprises a phase comparator having an operation range with specific limits for phase comparing A voltage-controlled oscillator produces an output at the output of the phase locked loop At the same time, the oscillator output is fed to the phase comparator A detector circuit, supplied with the output of the phase comparator, detects any exceeding of a specific limit of the phase by comparing the operation range of the phase comparator with a phase deviation of the oscillator output signal fed to the phase comparator The detector produces an output correction voltage An adder circuit adds this output correction voltage and an output error voltage of the phase comparator and supplies the resulting added voltage, as a control voltage, to the voltage-controlled oscillator This phase locked loop operates in a state wherein the lock range thereof has been equivalently expanded by the correction voltage

Electrostatic spray nozzle system

Abstract: A system for electrostatic spraying of liquids, such as agricultural pesticides, paints and other liquids, which relies on a novel spray nozzle that combines pneumatic atomization and electrostatic induction charging to provide a stream of electrostatically charged fine droplets. The nozzle uses a low voltage power supply, e.g. a 12 volt battery, electronically raises the voltage to a level in the range of several hundred to several thousand volts, and applies the high voltage to an annular induction electrode which is embedded in the spray nozzle. The high voltage components are inside the nozzle, which is made of an electrically insulating material, to minimize the danger of shock and the possibility of mechanical damage to the high voltage components. The spray nozzle operates at a relatively low voltage and at a low input power, but provides a droplet stream at a high droplet charging level, for effective and uniform deposition of the sprayed liquid onto the target.

Surface potential equilibration method of setting charge in charge-coupled devices

Abstract: A method of setting charge in a charge-coupled device (CCD) is described whereby the input diode is suitably pulsed and an amount of charge is retained in a potential well under the first transfer electrode. It is shown that, within limits defined by the operating potentials of the device, the sizes of the generated charge packets are linearly dependent on the voltage difference between the first transfer electrode and the input gate. They are also independent of threshold voltage. The method has important applications in all CCD's where it is necessary to obtain a linear low noise charge input that is uniform from one device to another. The linearity has been demonstrated with a 64-element CCD which with a sinusoidal input shows second and third harmonics to be 40 dB down from the fundamental. Measured rms input noise was above the minimum theoretically achievable value but was still 80 dB down from the peak signal level. The electrode area was 2000 μm2. For a comprehensive review on CCD's and input circuits, see [10].

An improved method for the digital protection of high voltage transmission lines

Abstract: This paper explores the accuracy of the digital methods for protection of high voltage transmission lines under transient fault condition on a long line and describes an improved method for future digital protection schemes. With this method it is possible to calculate R and L of high voltage transmission lines so that any number of harmonics on the current and voltage waveforms can be eliminated and it is shown to be suitable for distance protection during the first cycle of fault occurrence.

Battery condition monitoring method and apparatus

Abstract: A battery condition monitoring device and technique which senses battery terminal voltage at a predetermined time period after initial loading of the battery and determines battery condition as a result of such tests. A function of the terminal voltage is created and the time period determined by the length of time required for that function to reach a predetermined level. The test is performed on the slope of the terminal voltage transient.

Electrical Characterization of a Corona Discharge for Surface Treatment

Abstract: Electrical characterization is based on a display of voltage and charge which appears as a simple parallelogram. The area is a measure of energy input per cycle and is independent of voltage waveform but very dependent on the maximum voltage. A useful model for such corona discharges employs a Zener diode to simulate the corona drop. The buffer dielectric plays a major roll in controlling the corona power, and the air gap importance depends on the electrode system employed. Proper interpretation of the voltage-charge traces provides insight as to the corona performance and serves as a diagnostic procedure for obtaining optimum performance.

Electrostatic air cleaning apparatus

Abstract: An electrostatic air cleaning apparatus having a source of relatively large magnitude electrical voltage. The cell comprises a charged ionizing section and a collecting section comprising a charged grid and a grounded grid sandwiching therebetween a sheet of foraminous filter media. One of the grids is movable relative to the other grid. A single bus bar electrically connects the ionizing section and the charged grid to the source of voltage. The movable grip is positioned with respect to the stationary grid via support surfaces. Retainers maintain the movable grid in its desired position.

Chopper ballast for gaseous discharge lamps with auxiliary capacitor energy storage

Abstract: A single phase, high frequency chopper ballast without large magnetic and capacitive components for gaseous discharge lamps such as the Lucalox R lamp is operated on full wave rectified line voltage. A small auxiliary capacitor stores energy during the peaks of the rectified line voltage when the voltage is high enough to maintain lamp discharge. During the low voltage valley regions the auxiliary capacitor is discharged to supply augmented chopper input voltage or load circuit voltage and provide energy to maintain lamp ionization during the valley regions until the rectified line voltage rises to a usable level.

Battery monitoring apparatus

Abstract: A method and apparatus for continuously monitoring the remaining ampere hours of charge of a rechargeable battery. The invention utilizes a voltage monitoring system actuated by a current monitoring system to measure battery terminal voltage only when current discharge attains a predetermined level. The value of terminal voltage measured is stored and applied to an indicating device to yield a constant readout of battery state of charge.

Dynamic braking in controlled current motor drive systems

Abstract: A current source power converter for an electric motor is comprised by a combined controlled rectifier and chopper which is coupled to a controlled-current inverter by a dc reactor. In the motoring mode the combined rectifier and chopper functions as a phase controlled rectifier to control the current magnitude. In the dynamic braking mode a line switch is opened and a braking resistor placed across the rectifier output, and the combined rectifier and chopper is operated as a chopper to control the average voltage across the braking resistor and thus the current magnitude during braking.

Electronic circuit using field effect transistor with compensation means

Abstract: A compensation circuit for electronic circuits such as pulse generator circuits which are suitable for MOSICS includes a resistor of high resistance and parallel-connected MOSFETs of the enhancement type and depletion type, respectively. The drain electrodes of the MOSFETs are connected to a power supply through the resistor, and are also connected to the gate electrode of load MOSFET of the depletion type which constitutes a load for a MOSFET of the enhancement type. To the gate of the former enhancement type MOSFET, a controlled bias voltage is applied from the connection point of MOSFETs connected in series between the power supply and ground. By employing the compensation circuit in pulse generator circuits, the instability of the oscillating periods due to changes in the ambient temperature and changes in the supply voltage is compensated. Also, the differences of oscillating periods are decreased among MOSICs.

Electrostatic spray coating apparatus

Abstract: An improved electrostatic spray charging device for spray guns is disclosed The device comprises an adapter formed from a dielectric material in the shape of a generally cylindrical tube adapted at one end to be secured to the end of a conventional spray gun and constructed at the second end to provide an inductive charging field for materials discharged by the spray gun The second end of the adapter is formed, in the preferred embodiment, into two diametrically opposed lobes, each of which carries on its interior surface at least one charging plate to which a dc voltage on the order of 10-20 KV is applied The exterior surface of each lobe carries an electrically grounded electrode which preferably is annular in shape to provide an electric field configuration that prevents accumulation of charged spray particles on the exterior surfaces of the adapter

Cryogenic power cable

Abstract: A cryogenic power cable of a cryoresistive type having a conductor which is cooled with a cooling medium to permit large capacity power transmission by reducing thereby the electric resistance and the joule loss of the conductor. The temperature of the cable core is controlled through an ingenious arrangement comprising the conductor which incorporates therein a passage for the cooling medium, an electric insulation layer made of an ordinary electric insulating material and a thermal insulating material layer. The cable not only makes ultra-high voltage transmission of 500 to 1000 KV possible but also is advantageous on account of a simple and economic structure.

Fast ADC

Abstract: A novel ADC is described, consisting in its simplest and fastest version of a parallel ADC supplying the most significant bits, plus several suitably-connected difference amplifiers in which the input signal undergoes successive folding. Their common output is fed into another parallel ADC which supplies the least significant bits. The conversion rate is of the order of 400 MHz for eight bits. Several versions are described, yielding different trade-offs between speed and the number of discriminators employed.

Bilateral direct current converters

Abstract: Bilateral converters are disclosed which translate direct current voltages at one level to direct current voltages at another level. The same converter can also be used to translate direct current voltages at the second level back to direct current voltages at the first level. The converter is bilateral in the sense of converting direct current energy in both directions from a higher to a lower voltage level and from the lower to the higher level. A switching signal interrupts the direct current at the first voltage level and a transformer is used to step up or step down the voltage level. The output voltage is rectified to provide direct current power at the second voltage level. The same action takes place in the opposite direction in response to nothing more than a change in the loading placed on the system.

Monitoring system for voltage tunable receivers and converters utilizing voltage comparison techniques

Abstract: A system for remotely monitoring or determining the channel to which a voltage tunable receiver (or CATV converter) has been tuned includes an encoder for measuring the magnitude of the tuning voltage applied to the tuning section of the receiver and for generating a channel representative digital code in response to the tuning voltage. The digital code thus generated is compatible with remotely located monitoring equipment, and represents the number of the channel to which the receiver is tuned. Since the tuning voltage is not linearly related to the channel number of the station being received, the encoder utilizes a read-only memory or the like for storing a coded representation relating the channel number to the tuning voltage. In a preferred embodiment, the coded representations are sequentially stored as tuning voltage representations in address locations of the memory corresponding to the respective channel numbers. The read-only memory locations are sequentially addressed, and the tuning voltage representations are compared with the amplitude of the tuning voltage currently being applied to the receiver. When the value of the tuning voltage representation equals or exceeds the amplitude of the tuning voltage, the sequential addressing is terminated and the address of the last accessed memory location is stored to provide a coded indication of the channel number of the station being received.

Kinetic properties and inactivation of the gating currents of sodium channels in squid axon.

Abstract: Associated with the opening and closing of the sodium channels of nerve membrane is a small component of capacitative current, the gating current. After termination of a depolarizing step the gating current and sodium current decay with similar time courses. Both currents decay more rapidly at relatively negative membrane voltages than at positive ones. The gating current that flows during a depolarizing step is diminished by a pre-pulse that inactivates the sodium permeability. A pre-pulse has no effect after inactivation has been destroyed by internal perfusion with the proteolytic enzyme pronase. Gating charge (considered as positive charge) moves outward during a positive voltage step, with voltage dependent kinetics. The time constant of the outward gating current is a maximum at about minus 10 mV, and has a smaller value at voltages either more positive or negative than this value.

Transistor inverter motor drive having voltage boost at low speeds

Abstract: A transistor inverter drive provides variable frequency and variable voltage power to an electric motor and pulse width modulates a predetermined number of harmonic-reduced constant volt/hertz pulses per cycle of motor frequency to selectively vary the motor stator voltage so that constant torque over a wide speed range can be accomplished and increases the number of constant volt/hertz PWM pulses per motor frequency cycle at low motor speeds to boost the stator voltage and thereby compensate for decrease in magnetizing current and in torque which would otherwise occur at low frequencies Particularly, the drive has first and second oscillators for respectively deriving trains of first and second clock pulses whose frequencies vary at different rates as a function of an analog speed signal; a frequency switch which selects the higher frequency train of clock pulses; a volt/hertz integrator which derives ramp pulses whose leading edges are established by the pulses from the frequency switch and which vary in magnitude as a function of the time integral of the inverter bridge output voltage; a first comparator for deriving a first control pulse when each ramp signal becomes equal to a first reference voltage; a three phase generator for deriving three phase reference waves synchronized to the first clock pulses and displaced 120° and each of whose period includes a predetermined number of first clock pulses; and means for controlling the fundamental output voltages of individual phases of the inverter bridge in accordance with respective reference waves and including pulse width modulation chopping means for controlling conduction of transistors of the bridge inverter by variable width PWM pulses whose leading edges are at the output pulses from the frequency switch and whose trailing edges are at the first control pulses, whereby the number of PWM pulses in each fundamental voltage cycle is controlled by the higher frequency pulse train and provides a boost in motor terminal voltage at low motor speeds

Using an Arbitrary Six-Port Junction to Measure Complex Voltage Ratios

Abstract: An arbitrary six-port junction is analyzed as a microwave vector voltmeter, measuring the amplitudes and phase difference of two input signals in terms of power readings taken at the remaining four ports The junction may be calibrated for measuring complex voltage ratios using a self-calibration procedure which requires no standards