Showing papers on "Voltage published in 1979"

Characterization of the electron mobility in the inverted l100g Si surface

Abstract: The effective mobility of electrons in the inverted 〈100〉 Si surface was measured over a wide range of temperatures, gate voltages, and back-bias voltages. At a first glance the mobility appears to be strongly dependent on the channel surface doping. When the data were reanalyzed under a new approach where the mobility is plotted as a function of an effective perpendicular electric field experienced by the inversion layer, a universal curve has developed from the experimental data which indicates that the inversion layer mobility is not a function of doping density in the range (N A 2 system and not a parameter sensitive to nominal process variations encountered in the present n-channel Si-Gate Technology.

Method of charging batteries and apparatus therefor

Abstract: A method of fast charging batteries by means of precise analysis of the profile of the variation with time of a characteristic of the battery which is indicative of the variation in stored chemical energy as the battery is charged. The method specifically comprises analyzing the profile for the occurrence of a particular series of events preferably including one or more inflection points which precisely identify the point in time at which the application of a fast charge rate should be discontinued. Additional methods of analysis provide for termination or control of the charging current upon the occurrence of other events such as limiting values on time, voltage or voltage slope or a negative change in the level of stored energy. Apparatus for performing these methods comprises a suitable power supply and a microcomputer for analyzing the profile and controlling the power supply.

Basic properties of the electrolyte—SiO 2 —Si system: Physical and theoretical aspects

Abstract: In order to provide an improved understanding of ion-sensitive field-effect transistors (ISFET's) an analysis of the quasi-equilibrium characteristics of an electrolyte-oxide-semiconductor (EOS) system has been carried out. The characteristics of this system are examined by initially considering two limiting cases. In the first case, an ideal unblocked interface between the electrolyte and the oxide is assumed. Electrochemical processes of ion exchange dominates and consequently, a Nernstian response is experienced. The second limiting case assumes a totally blocked interface such that the behavior of the EOS system is dictated by electrostatic factors. The analysis is then generalized to examine the case of an electrolyte-pyrogenic SiO 2 -Si system using a site binding model to describe the ionic adsorption processes at the electrolyte-pyrogenic SiO 2 interface. The C-V characteristics and changes in flat-band voltage of the EOS system in response to pH are examined. Analytical results show that in general, the response does not obey the classical Nernst equation. Correlation of theoretical and experimental results yields excellent agreement suggesting that the models used in this study can provide an adequate description of the physical processes.

1 µm MOSFET VLSI technology: Part IV—Hot-electron design constraints

Abstract: An approach is described for determining the hot-electron-limited voltages for silicon MOSFET's of small dimensions. The approach was followed in determining the room-temperature and the 77 K hot-electron-limited voltages for a device designed to have a minimum channel length of 1 µm. The substrate hot-electron limits were determined empirically from measurements of the emission probabilities as a function of voltage using devices of reentrant geometry. The channel hot-electron limits were determined empirically from measurements of the injection current as a function of voltage and from long-term stress experiments. For the 1 µm design considered, the channel hot-electron limits are lower than the substrate hot-electron limits. The maximum voltage, V_{DS} = V_{GS} , is 4.75 V at room temperature (25°C) and 3.5 V at 77 K. More details of the voltage limits as well as the approach for determining them are discussed. Examples of circuits designed with these devices to operate within these hot-electron voltage limits are also discussed.

A low-voltage CMOS bandgap reference

Abstract: The CMOS bandgap voltage reference described here uses the bipolar substrate-transistor and the bipolar-like source-to-drain transfer characteristics of MOS transistors in weak inversion to implement a voltage source that is proportional to absolute temperature (PTAT). A first version of PTAT source is derived from a circuit described previously. A second version is based on a novel cell that can be stacked to obtain the desired voltage. Both versions operate down to 1.3 V with a current drain below 1 /spl mu/A. A stability of 3 mV over 100/spl deg/C has been obtained with a few nonadjusted samples. Experimental results suggest some possible improvements to extend this stability to every circuit.

System and method for charging electrochemical cells in series

Abstract: A battery charging system capable of equalizing the charge of each individual cell at a selected full charge voltage includes means for regulating charger current to first increase current at a constant rate until a bulk charging level is achieved or until any cell reaches a safe reference voltage. A system controller then begins to decrease the charging rate as long as any cell exceeds the reference voltage until an equalization current level is reached. At this point, the system controller activates a plurality of shunt modules to permit shunting of current around any cell having a voltage exceeding the reference voltage. Leads extending between the battery of cells and shunt modules are time shared to permit alternate shunting of current and voltage monitoring without the voltage drop caused by the shunt current. After each cell has at one time exceeded the reference voltage, the charging current is terminated.

Bridge converter circuit

Abstract: A converter includes a full-wave bridge network across which operating voltages of +E and -E volts are applied, diagonal legs of the bridge each including two semi-conductor switches connected in series between individual operating voltage and output terminals, two diodes polarized in one direction being connected for conducting current from a point of reference potential to the centralmost switches of the two upper legs, respectively, and another two diodes like polarized in another direction being connected for conducting current from the centralmost switches of the two lower legs, respectively, to the point of reference potential. Each diode and its associated switch form a unidirectional gated current path and the vertically opposing centralmost switch and diode pairs of the upper and lower legs form a bidirectional gated current path. The switches are operable for providing zero, +E, +2E, -E, and -2E volts across a load in some predetermined sequence for producing a desired AC voltage waveform across the load. The diodes also serve to clamp the common connections between their associated two semiconductor switches to within a diode drop of the reference potential, thereby protecting the switches from overvoltage.

Photoelectrolysis of water with semiconductors

Abstract: The use of semiconductors, as photoelectrodes in electrolytic cells for the electrolysis of water, is described and the results reported in the literature for various semiconductors are reviewed. The most important properties of the semiconductor are shown to be the band-gap energyE g , and the flat-band potentialU fb . The semiconductor absorbs photons that are more energetic than the band-gap energy and creates electronhole pairs. These charge carriers can be separated before recombination by the electric field at the semiconductor-electrolyte interface. For electrolysis to proceed, the potential corresponding to the band gap must appreciably exceed the standard potential for the electrolysis of water, 1.23 volts. In addition, the flat-band potential must be more negative than the hydrogen potential or an external bias voltage is required. The semiconductor must not corrode under the operating conditions and must permit transfer of the minority carrier to the electrolyte. The current theories of charge transfer and reaction mechanism are discussed.

A Review of Electrical Breakdown in Mixtures of SF6 and Other Gases

Abstract: The outstanding electrical and arc-quenching characteristics of sulphur-hexafluoride (SF6) have already set new trends and standards for the construction of high voltage equipment. Intensive research is being carried out on the electrical properties of SF6, other electronegative gases and their mixtures with more common gases. The aims are to obtain an economical insulation with optimal electrical properties and to acquire a better understanding of their prebreakdown and breakdown behavior. Recently [1] we reviewed the breakdwon mechanisms operating in compressed gases and discussed the theoretical results in the light of experimental measurement in SF6. This paper deals with the breakdown and prebreakdown behavior of SF6 mixtures with other electron attaching and non-attaching gases. Uniform and non-uniform field breakdown under the applications of direct, alternating and impulse voltages is discussed. Improvement in properties such as higher breakdown voltages in non-uniform field gaps, less sensitivity to the electrode surface roughness and to the presence of contaminants and improved arc interruption characteristics of SF6-gas mixtures are discussed.

Simple theory of free-burning arcs

Abstract: Analytic formulae are derived from the controlling physical equations to give the principal characteristics of free burning arcs. Predictions of arc radius, voltage, central temperature, electric field and centre plasma velocity are in reasonable agreement with published experimental results for arcs in air from 1 A to 20,000 A at a pressure of 1 atmosphere and an electrode spacing of 1 cm. The theory enables useful predictions to be made for applications of arcs in welding, switchgear and arc furnaces.

Solid-state regulated voltage supply

Abstract: A solid-state (IC) regulated voltage supply compensated for effects of changes in temperature comprising first and second transistors operated at different current densities. Associated circuitry develops a voltage proportional to the Delta VBE of the two transistors and having a positive temperature coefficient. This voltage is connected in series with the VBE voltage of one of the two transistors, having a negative temperature coefficient, to produce a resultant voltage with nearly zero temperature coefficient. A feedback circuit responsive to current flow through the two transistors automatically adjusts the base voltages to maintain a predetermined ratio of current density for the two transistors. Other embodiments provide higher-level DC outputs and compensation for base current flow.

The calcium current and the activation of a slow potassium conductance in voltage-clamped mouse neuroblastoma cells.

Abstract: 1. The Ca2+ inward current (ICa) and a slow outward current in differentiated cells of mouse neuroblastoma clone N1E-115 have been studied under voltage-clamp conditions. 2. ICa shows voltage- and time-dependent inactivation when evoked by step-wise depolarizations in Na+-free solution containing high [Ca2+] (20 nM) and tetraethylammonium (TEA, 25 mM). Ba2+ and Sr2+ can substitute for Ca2+. 3. Holding potentials below -70 mV maximal activate ICa. Half inactivation occurs at -56 mV and ICa is completely inactivated beyond holding levels of -30 mV. Maximum peak currents are of the order of 10(-4) A/cm2 and the reversal potential ranges from +40 to +60 mV. The ICa inactivation time course follows first-order kinetics with a voltage-depedent time constant ranging from 25 to 100 msec. 4. The striking resemblance between ICa and the Ca2+ current in the unfertilized mouse oocyte (Okamoto, Takahashi & Yamashita, 1977) is discussed. 5. A slow outward current with a rise time of several seconds is recorded on voltage steps beyond -20 mV in high [Ca2+] solutions. It is carried primarily by K+ on account of the value of the reversal potential and its dependence on [K]0. This K+ current is TEA-insensitive and is blocked by Ca2+ antagonists. 6. The slow K+ current (IK(Ca)) is suggested to be mediated by Ca2+ influx, but the voltage-dependence of the underlying conductance (GK(Ca)) differs significantly from the ICa voltage-dependence. 7. The results are consistent with the hypothesis that IK(Ca) depends both on ICa and on membrane potential. An alternative hypothesis is briefly discussed.

Bimorph piezoelectric flexible mirror

Abstract: We describe a flexible mirror constructed from plates of glass and lead zirconium titanate (PZT) piezoelectric ceramic glued together. It is activated by a series of electrodes on the reverse side. An equation of state is derived, giving the surface profile as a function of the electrode voltages, and the experimental behavior of the mirror is illustrated.

Battery testing apparatus with overload protective means

Abstract: An apparatus for testing storage batteries under no-load and load conditions is provided which limits the duration of a test of any battery having adequate charge capacity and thereby protects both the apparatus and the battery from the hazards of excessive current. The battery testing apparatus includes a load circuit having current responsive switch means that automatically opens when its predetermined amperage rating is exceeded to provide a load test having a duration corresponding to the reaction time of the switch means. A voltage indicator, including a lamp or a voltmeter, detects and indicates the relative magnitude of the voltage available between the terminals of the battery so that the charge capacity of the battery can be determined both under no-load and load conditions. An ammeter may be also included for measuring the current passing through the load circuit during the load test.

A two‐junction cascade solar‐cell structure

Abstract: A two‐junction cascade solar‐cell structure has been demonstrated in the AlGaAs/GaAs materials system. The cell consists of two p‐n junctions with different band gaps monolithically connected in series by means of a low‐resistance p‐n junction. An open‐circuit voltage of 2.0 V has been observed for this cascade structure. This is the highest open‐circuit voltage that has been reported for a single monolithic photovoltaic cell.

Circuit arrangement for the operation of recording nozzles in ink mosaic recording devices

Abstract: A circuit arrangement for the operation of recording nozzles in ink mosaic recording devices employing tubular drive elements, which contain recording fluid, and which comprise electromechanical transducers, in particular piezo-electric transducers, whose diameter, and thus internal volume varies in the presence of different voltage potentials, utilizing an electronic switch for each of the electromechanical transducers, for selectively supplying to the respective electromechanical transducers a first voltage potential, and an electronic switch common to all of said electromechanical transducers for supplying in common a second voltage potential to all of said electronic transducers. The first voltage potential preferably is a potential operative to expand the diameters of the electromechanical transducers, and said second voltage potential preferably is a potential operative to contract the diameters of the electromechanical transducers. Means may also be provided in the supply path of current conducted across the electronic switch supplying the first voltage potential to the electromechanical transducers for limiting such current in an adjustable manner.

Characteristics and limitation of scaled-down MOSFET's due to two-dimensional field effect

Abstract: Practical limitations of minimum-size MOS-LSI devices are investigated through measurement of experimental devices. It is assumed that scaled-down MOSFET's are limited by three physical phenomena. These are 1) poor threshold control which is caused by drain electric field, 2) reduced drain breakdown voltage due to lateral bipolar effects, and 3) hot-electron injection into the gate oxide film which yields performance variations during device operation. Experimental models of these phenomena are proposed and the smallest possible MOSFET structure, for a given supply voltage, is considered. It is concluded that the smallest feasible device has a channel length of 0.52 µm and a gate oxide thickness of 9.4 nm when the supply voltage is 1.5 V. Reliable threshold control is most difficult to realize in an MOS-LSI with the smallest devices.

Gas flow measuring apparatus

Abstract: A gas flow measuring apparatus includes first and second temperature dependent resistors located in a gas tube respectively downstream and upstream of an electric heater which is also located in the gas tube. The first and second temperature dependent resistors are connected to form a bridge circuit together with first and second reference resistors. Between a pair of diagonal junctions of the bridge circuit, a potential difference is produced depending on the flow rate of the gas and the power supplied to the electric heater, and a measuring circuit controls the power supplied to the electric heater so that the potential difference is maintained at a predetermined value irrespective of a change in flow rate of the gas. The measuring circuit includes a chopper circuit to convert the potential difference into a square wave having a peak-to-peak value substantially equal to the potential difference and having a center reference level of the square wave corresponding to a voltage level determined by a reference voltage generator and an adder circuit. The square wave from the chopper circuit is then amplified and half rectified and applied to a sample-hold circuit to produce a voltage signal representative of the potential difference. A differential amplifier having two inputs of the voltage signal from the sample-hold circuit and a predetermined voltage produces an output signal which is used to control the power supplied to the electric heater. A current flowing into the electric heater is used to determine the flow rate of the gas.

A new type of amorphous silicon photovoltaic cell generating more than 2.0 V

Abstract: A new type of plasma‐deposited amorphous silicon photovoltaic cell having a horizontally multilayered p‐i‐n unit‐cell structure has been developed. The open‐circuit voltage Voc is nearly proportional to the number of repetitions of the p‐i‐n unit cell. Almost‐constant energy‐conversion efficiencies of around 4% have been obtained with Voc ranging from 0.6 to 2.4 V by applying a simple optimum design rule to the cell‐construction parameters.

Electrically integrated touch input and output display system

Abstract: A user touch input and output display system which combines elements of a capacitive attenuator type touch switch and a display into a single system. In one embodiment type, one of the electrodes of the display performs double duty as a rear pad, for example a transmitter pad, of a capacitive attenuator type touch switch. The other rear pad necessary for operation of a capacitive attenuator touch switch may either be within the same chamber or envelope as the display electrodes, or may be outside the chamber. The display may for example be a gas discharge display, and the shared electrode does double duty as the display anode and a touch switch transmitter pad. Alternatively, the display may be a liquid crystal display. In embodiments where the other rear pad is within the chamber, to avoid noise interference to the touch switch caused by the gaseous discharge, it is preferable to operate the system in a display mode and in a touch switch mode at different times. During the touch switch mode, the display anode which also serves as the touch switch transmitter pad is supplied with an effectively AC signal. During the display mode, the display anode may be supplied with either a pulsating or a steady DC voltage. In another embodiment type, a liquid crystal display is driven by an AC voltage source having a high series impedance, and a display electrode is capacitively coupled to a touch pad. When a user touches the pad, sufficient signal is shunted to ground to drop the voltage across the display electrode below that necessary to maintain visible energization.

Parametric Analysis of Grounding Grids

Abstract: The results of an extensive study conducted using a computer program designed to determine grounding performance in two-layer soils [1,2,3,5] are described and discussed. A variety of grounding grid configurations and two-layer soil conditions are analysed in detail. The calculated grounding resistances, step and touch potentials are summarized in several charts which could be used conveniently for practical design purposes. The results obtained prove that in general, conventional methods of analysis, such as the IEEE 80 method [4] which uses "Km & Ki" irregularity factors, fail to predict accurately grounding grid performance. Also, it is shown that there are certain grid configurations and/or burial depth, which lead to optimum touch or mesh potentials. Finally, it is shown that certain two-layer conditions will lead to considerably higher touch (or mesh) potentials than the other comparable alternatives.

Optical Measurement of Current and Voltage on Power Systems

Abstract: The basic principles of optical methods for measuring voltage and current at high voltage are presented. These include the magneto-optic effect, the electro-optic effect and the electrogyration effect, plus various detection and noise-reduction techniques. Both free-path and enclosed-path devices which have been constructed on these principles are described. The viability of these devices for the electricity-supply industry is assessed.

Method of charging a vehicle battery

Abstract: A new method of charging a vehicle battery is disclosed. The proposed method employs electronically controlled data processing device, which controls battery charging condition in accordance with temperature, battery electrolyte, external electric load as well as battery voltage. As a result, voltage drop due to over loading may be prevented and a stable battery charging voltage may be obtained.

Base drive and overlap protection circuit

Abstract: An inverter (34) which provides power to an A. C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A. C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A. C. machine is optimized. The control circuit includes a microcomputer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). A base drive and overlap protection circuit is included to insure that both transistors of a complimentary pair are not conducting at the same time. In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

ac induced corrosion. The effect of an alternating voltage on electrodes under charge-transfer control

Abstract: The equation relating current to voltage for an electrode under charge-transfer control has been solved for a sinusoidal modulation of the electrode potential. The rectified Faradaic component has been obtained, so as to derive its value as a function of the Tafel parameter and of the amplitude of the modulating voltage, as well as of average electrode potential. The case where one electrode reaction is under diffusion control also has been treated. The amplitude and phase characteristics of the harmonic components have been derived, and their use for determining the kinetic properties of the electrode have been discussed. The capacitative current generated by the alternating voltage also has been investigated, and the conditions under which it can be separated from the Faradaic current have been given. The implications of these results on the corrosion due to AC leakage have been examined.

Detector for detecting voltage breakdowns on the high-voltage side of an electric precipitator

Abstract: A detector for detecting breakdowns on the high-voltage side of an electric precipitator, the voltage of which is supplied from an a-c network through a thyristor control circuit, a high-voltage transformer and a rectifier. The improvement of the invention comprises means for continuously comparing characteristic parameters of successive half-waves of variations of the voltage at the precipitator. A predetermined deviation of the characteristic parameters comprises a criterion for determining a breakdown of the precipitator voltage.

Charging Current Data for Guesswork-Free Design of High-Resistance Grounded Systems

Abstract: The design of high-resistance grounded power systems requires the sizing of the grounding resistor to provide a current flow equal to or greater than three times the system charging current (I co ) of each phase. In industrial power systems the insulated power cables are a major source of system charging current which flows into line-to-ground faults. Data are presented which will allow cable charging currents to be quickly and precisely determined after the cable size, voltage, footage, insulation type, and thickness have been determined. Charging current data for transformers, motors, generators, and capacitors are also included.

Vibration type transducer

Abstract: PURPOSE: To measure a strain with high accuracy with a simple constitution by selecting a drain resistance, capacitance between a drain and substrate, and oscillating angular velocity so that their product can become extremely larger than '1'. CONSTITUTION: Since a negative potential is applied across a mobile electrode 30 from a DC power source E2, electrons are forcibly pushed toward the inside of a silicon substrate 24 from the lower surface of the vibrator 30 and, on the contrary, holes (p-type) are attracted toward the surface of the substrate 24. Because of the holes, a channel CNN composed of a p-type conductive layer is formed on the surface of the substrate 24 and an electric current i d flows between a source S and drain D. The voltage the drain D generated by the current i d is shifted in phase by a drain resistance RD and the capacitance CD formed between the drain and substrate 24 and, due to the potential change, the electrostatic attracting force between the electrode 30 and drain D changes, resulting in a change in the interval X between the electrode 30 and drain D. The oscillation caused by the potential change continues when the resistance RD, capacitance CD, and oscillating angular velocity ω are selected so that their product can become extremely larger than '1'. When a pressure PM is applied to the substrate 24, a strain is applied to the electrode 30 and its characteristic frequency varies. The pressure PM is detected by fetching the variation. COPYRIGHT: (C)1993,JPO&Japio

EPROM Reliability test circuit

Abstract: On-chip circuitry for measuring the threshold voltage and hence the data retention reliability of the floating gate transistors used in erasable programmable read-only computer memories. Upon the application of a program "verification" signal, an externally adjustable and calibrated voltage ramp is applied by the test circuit to each of the memory X-lines coupled to the gate elements of the memory transistors. The threshold voltage of a selected transistor can then be determined by increasing the voltage ramp to the point at which the transistor will read out.