Showing papers on "Voltage published in 1973"

Device for operating dental hand pieces

Abstract: A device which can be used for operating a dental hand piece with a motor drive and a dental hand piece with a pneumatic drive, such as a turbine drive, has an electric circuit and a potentiometer connected to the input of the circuit and varying the voltage at its output. An electric valve varies the flow volume of the compressed air supplied to the pneumatic drive. A switching device connects selectively the electric motor and the electric valve with the output of the circuit.

A method for analyzing waves in structures consisting of metal strips on dispersive media

Abstract: A method for analysis of wave propagation on structures consisting of periodic metal strips is presented. The method is an extension of earlier theories based on Legendre polynomial expansions of the electric field. The extension allows analysis of strips on any material or layers of materials, provided the electromagnetic properties can be expressed in terms of a wavenumber-dependent permittivity. Layers of dielectrics, piezoelectrics, semiconductors, and metals are typical of the materials of practical interest in connection with surface wave acoustics. Strip configurations such as interdigital transducers, multistrip directional couplers and reflectors, and strip coupled amplifiers can be analyzed by the present approach. Prescriptions for calculating the amplitudes of the space harmonics of the electric field strength are given. Closed-form expressions for strip current and voltage are developed.

The positive dynamic current and its inactivation properties in cardiac Purkinje fibres

Abstract: 1. The positive dynamic current in sheep cardiac Purkinje fibres was studied using ;voltage clamp' technique. The major portion of this current was carried by Cl(-) ions.2. A pre-step in membrane potential changed the response of this current to a subsequent depolarization in a way that is similar to the Na inactivation process described by Hodgkin & Huxley (1952a, b).3. Recovery of this current after its activation could be described reasonably well by a single exponential process, and the time course of the recovery varied with membrane voltage.4. The relation of steady-state inactivation of the current to membrane voltage showed a sigmoid shape, varying from 100% at membrane potential of -30 mV to 0% at -80 mV. The membrane potential at 50% inactivation was -53 mV.5. The Cl(-) current may play a role in the shape of the Purkinje fibre action potential, but exact definition depends on determining the voltage and time dependence of all the ionic currents that flow during the plateau.

Method of measuring the charge condition of galvanic energy sources and apparatus for carrying out this method

Abstract: A method and apparatus for measuring the charge condition of galvanic energy sources by means of an integrating measuring device, in which the charging current or a magnitude proportional thereto is weighted with a factor dependent on the predetermined gassing voltage which changes with temperature and is matched in its timely behavior to the charging condition of the energy source, and possibly also by a factor dependent on the respective battery temperature and dependent of the charging condition, before it is fed to the integrating measuring device; the discharge current or a magnitude proportional thereto is thereby multiplied with a factor dependent on the respective battery temperature and subsequently is raised to the power with an exponent (1 + m) whose term m itself is variable as a function of the battery temperature before it is fed in its turn to the integrating measuring device.

An analysis of the threshold voltage for short-channel IGFET's

Abstract: For short-channel insulated-gate field-effect transistors (IGFET) operating with source-to-substrate reverse bias, the threshold voltage is in general a function of channel length and drain-to-source voltage. It is shown in this analysis that these dependences can be attributed to the two-dimensional distribution of the depletion charges. Starting from two fundamental relations, the overall charge neutrality and the voltage relations based on the energy band diagram, a generalized threshold voltage equation in integral form is derived. A closed-form threshold equation is then obtained using a regional approximation with a simplified piecewise-linear depletion profile. The equation includes as new factors, the channel length, junction depth and drain voltage, and passes to the conventional form for increasing channel length. The theoretical threshold voltage expression is found to predict the correct tendencies and is shown to be in reasonable agreement with experimental measurements.

Electric camera shutter with voltage checking circuit

Abstract: A camera in which a circuit for automatically determining the extent to which film is exposed has a voltage source and a checking circuit for checking the condition of the voltage source. The checking circuit includes a meter to indicate the condition of the voltage source, a resistor and a diode connected in series in a forward direction between the resistor and the meter, and a normally open switch between the resistor and the voltage source to be closed for connecting the resistor and diode to the meter so that the latter will give a reading indicating the condition of the voltage source. In this way the diode prevents the checking circuit from influencing the meter when the checking switch is not closed.

Detection of optical and infrared radiation with DC-biased electron-tunneling metal-barrier-metal diodes

Abstract: The voltage obtained from metal-barrier-metal (MBM) diodes by phase-sensitive detection when illuminated with optical and near-infrared radiation, modulated at 880 Hz, has been studied as a function of an applied dc bias. The detected voltage is a nonlinear function of the bias voltage for high junction impedances, and linear for low junction impedances. The nonlinearity in the junction has been shown to be consistent with electron tunneling theory.

Thin‐film LiNbO3 electro‐optic light modulator

Abstract: An out‐diffused planar optical waveguide in LiNbO3 has been used to produce an efficient broad‐band electro‐optic phase modulator. The ratio of modulation index η and voltage is 0.13 V−1, the maximum base bandwidth with 50‐Ω load is 3.2 GHz, and the modulating power per unit bandwidth for η=1 rad is 0.2 mW/MHz.

Electronic dust separator system

Abstract: A device for electronic collection of dust which includes an electrostatic separator and a high voltage transformer which, in conjunction with a pulse generator, supplies a pulse voltage to the separator. The output voltage of the pulse generator is superimposed on the output voltage of the transformer to cause the voltage at the electrostatic separator to exceed the spark over limit, once each cycle of the transformer output.

Method and apparatus for determining internal impedance of animal body part

Abstract: Apparatus and a method for determining the internal impedance of a portion of an animal body. Two electrical currents of different frequencies are passed through the body portion and the voltage across the body portion corresponding to each current flow is sensed. In-phase coherent detection is performed to remove the out-of-phase signal components and the resulting in-phase voltage signals are subtracted from each other to yield a measure of only the internal impedance of the body portion. The invention is especially suitable for use in measuring the changes in the amount of fluid in the human lung.

Electronic rotational sensor

Abstract: A circuit for sensing the rotational rate of electric motor driving apparatus, such as a conveyor or material handler, wherein the motor driving the apparatus is deenergized upon the apparatus rate of rotation decreasing below permissible limits. A pulsating electronic signal having a frequency determined by the rotating apparatus is created by electronic light sensing means and the pulsating signal is modified to create pulses of equal duration. Charging means in the form of capacitors produce a ramp voltage at a rate proportional to the rate of apparatus rotation, and is discharged by an SCR controlled by the modified signal. Upon the ramp voltage increasing beyond a predetermined level, electronic switch means are energized operating a relay which deenergizes the motor circuit. Bypass switch means are employed to permit manual starting of the motor to obtain an operational rate of rotation.

Second breakdown and damage in junction devices

Abstract: Second breakdown has been studied in silicon-on-sapphire (SOS) thin-film diodes using the stroboscopic technique of Sunshine. Nucleation of current filaments, filament growth, and damage through the formation of melt channels are observed and related to the voltage waveforms, geometry, and base layer resistivity. The delay time and the minimum energy for the onset of second breakdown are related to heating of the high-resistivity side of the junction. Theoretical models are presented to describe nucleation of current channels in the junction and the melt transition. A junction channel forms when the sum of minority carrier and thermally generated current densities becomes equal to the local applied current density. The voltage across the junction then goes close to zero locally, but the internal field is not "washed out." The channel is ballasted by the spreading resistance of the high-resistance region. The melt transition is described in terms of a single heat-transfer coefficient characteristic of the device type. As the melt filament grows, the voltage across the filament (and the device) falls. The threshold current for filamentation varies as (ρ-3/4), where ρ is the resistivity of the high-resistance region. Data on transistors are presented in support of the theoretical models.

Power source device for an electric surgical knife

Abstract: Power source device for an electric surgical knife for use with an endoscope comprising, means for supplying a high frequency signal to an electric surgical knife, a selector for determining whether or not the high frequency signal is attenuated before it is supplied to the knife, a level detecting circuit for detecting the voltage level of the high frequency signal which is attenuated and supplied to the treatment electrode of the knife, a level difference detecting circuit for detecting different voltages between the high frequency signal supplied to the treatment electrode and that supplied to the fixed electrode of the knife, and means for determining whether the conductive state of the knife is normal or abnormal using output signals from the level detecting circuit and level difference detecting circuit.

Battery peaking unit for fuel cell power plants

Abstract: An auxiliary storage battery or other DC rechargeable power source is connected in parallel with a fuel cell to supply additional current to a load when an overload such as the starting of a motor causes the fuel cell voltage to drop. The fuel cell voltage is sensed and when it reduces below a preselected value the auxiliary battery supplies current to the load for a preselected timed interval. The storage battery is recharged by power supplied by the fuel cell only during periods when the battery is not supplying current to the load. Excessive battery drain is prevented by shutting down the peaking unit whenever fluctuations in the fuel cell voltage cause multiple peaking cycles.

Power supply for refrigeration units

Abstract: An electronic power supply which derives power from a DC battery to operate the AC induction motor of a refrigeration compressor unit. The amplitude and frequency of the AC voltage developed by the power supply from the DC battery are functions of the battery voltage. When the battery voltage increases, the amplitude and frequency of the AC voltage for driving the motor increase and vice versa to thereby efficiently operate the motor in spite of fluctuation in the level of battery voltage.

High voltage electrical connector

Abstract: This invention relates to an insulated high voltage electrical connector for splicing together cable carrying high currents at high voltages More particularly, the invention includes a current-carrying connector housing which contains a power-driven piston assembly for driving wedge-shaped jaws onto the center conductor of the cable An internal shield positioned at either end of the housing modulates voltage potential lines to prevent dangerous stress buildup Between the housing and a molded external shield, a continuous body of insulation is provided Vent tubes provide escape means for otherwise trapped air and gases which could contaminate the semi-conductive and non-conductive members The integrity of the molded external shield is maintained by placing ignition wires through the ends of the connector to the power-driven piston assembly

Electrographic recording process and apparatus using conductive toner subject to a capacitive force

Abstract: An electrographic process and device are provided wherein a dielectric recording member is arranged between two electrodes to one of which is adherably bound electronically conductive toner powder, the toner powder providing an electronically conductive path between the electrode to which it is bound and the adjacent surface of the dielectric member, and a voltage applied to the electrodes for a time and of a magnitude sufficient to generate a force pattern of intelligence on the toner which enables toner deposition on the recording member in accordance with the force pattern The force pattern is generated directly on the toner rather than on the recording member which is passive in the operation of this invention

Controlled battery charger system

Abstract: A controlled battery charger system is provided wherein a rechargeable battery is charged at a high charge rate and the voltage and temperature of the battery are both monitored by sensing means which are coupled to switching means to shut off the high charge-rate current when either the temperature or the voltage of the battery reaches a predetermined level.

Laser stabilization technique

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.

System for eliminating substrate bias effect in field effect transistor circuits

Abstract: An integrated circuit, formed on a common substrate, having one portion operated from a first source of operating potential and another portion operated from a second source of operating potential. Separate wells are diffused in said substrate for the connection thereto of the different voltages and a reference potential common to the two sources of operating potential is applied to the common substrate. Transistors having a given potential applied to their source electrodes are formed in the common substrate or in a well having the same given potential connected thereto for eliminating potential differences between the source and the substrate of the transistors.

Power supply system

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.

Method for driving a plasma display panel

Abstract: The present invention discloses a method for writing information on a plasma display panel with the minimum write voltage. In the plasma display panel, an upper member and a lower member face each other, sandwiching a gap filled with gas therebetween, and the upper member had column electrodes covered with a dielectric layer and the lower member has row electrodes covered with a dielectric layer, and the upper and the lower members are not similar in construction and/or in the material of which they are made. In one embodiment, when a secondary electron radiation emissivity of the surface of the dielectric layer of row electrodes which are provided on the lower member is higher than a secondary electron radiation emissivity of the surface of the dielectric layer of column electrodes which are provided on the upper member, a write voltage is supplied to selected electrodes with a polarity such that the row electrodes become negative and the row electrodes become positive.

Pulse generator with automatic timing adjustment for constant duty cycle

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.

Theory of dynamic charge and capacitance characteristics in MIS systems containing discrete surface traps

Abstract: Theoretical studies have been made on the dynamic characteristics of the metal-insulator-semiconductor (MIS) capacitor containing discrete surface traps. It has been shown that when the surface traps are in dynamic equilibrium with the voltage ramp, the device exhibits steady-state charge and capacitance characteristics. When the surface traps are out of equilibrium with the voltage ramp, then the emission of trapped charge is a function of time only and not of voltage. Under such conditions, the characteristics are considered to be non-steady-state in nature. The emission of trapped charge in the non-steady state gives rise to a plateau or ledge in the C – V characteristics, while characteristics. The transition from the steady state to the non-steady state results in kinks in the characteristics. The physical processes involved have been stressed and simple expressions have been obtained for the charge and capacitance in terms of the trapping parameters, sweep-rate and temperature.

Method of driving liquid crystal display device

Abstract: A method of driving a liquid crystal display device including a liquid crystal layer provided with electrodes on its two opposite surfaces, comprising the steps of applying a first signal for designating the electrode position and a voltage signal having a higher frequency to the electrodes on one surface, and applying and input signal and the signal of said higher frequency to the electrodes on the other surface. The signals are controlled by another signal of different frequency to drive the display device with an ac voltage. Temperature compensation can be performed by varying the magnitude or the frequency of the voltage signal according to the temperature level.

Membrane shot-noise in electrically depolarized nodes of Ranvier.

Abstract: The power spectra of the spontaneous voltage fluctuations (membrane noise) of the node of Ranvier were measured in the frequency range from 0.3 to 1500 cycles per second at different levels of the membrane potential (−90 to +30 mV, inside negative). Up from about −30 mV the power spectrum shows a\(\frac{1}{{1 + \left( {2\pi f\tau } \right)^2 }}\) component, which increases with depolarization. This shot like noise component is independent of and occurs in addition to the 1/f component. The source of this shot like noise component is probably given by fluctuations in the conductance for potassium ions. With the use of a minimum parameter model which consists of channels that switch randomly in time from the closed to the open state and vice versa, independent of each other, the number of active channels per μm2 appears to be of the order of 1000. The elementary unit of the potassium system conductance is then of the order of 10−11S per channel1 and the mean frequency of switches per second per channels is about 160.

Ca-movement controlling myocardial contractility. I. Voltage-, current- and time-dependence of mechanical activity under voltage clamp conditions (cat papillary muscles and trabeculae).

Abstract: 1. Tension development and membrane currents have been measured in cat ventricular fibres applying a double sucrose-gap voltage clamp technique. 2. A well defined mechanical threshold was found at which a considerable all-or-non response occurred. This threshold obviously coincided with the threshold potential of the fast inward current (INa). Changes in [Cae] (0.8–7.5 mM) did not separate the two thresholds. Ramp clamps of decreasing steepness shifted the threshold of bothINa and that of tension development towards less negative potentials. Ramp clamps ineffective in elicitingINa did not produce phasic tension development. This suggests that a fast inward current normally triggers the internal Ca release. 3. In rhythmically activated preparations the steady state voltage-tension relationship rose roughly in parallel toICa in a S-shaped manner up to about zero potential. With further depolarizations the steady-state tension development tended to decline again. It was concluded that this voltage dependent gain of contractile activation reflects the time integral of transmembrane Ca supply provided from the extracellular space. 4. Under steady state conditions peak tension produced by square clamps of a given suprathreshold voltage rose with prolongation of the clamp duration up to a maximum at 500–700 msec. This maximum in turn depended on the clamp potential applied. From the results obtained, a tension-time-voltage relationship has been drawn. Even under very long lasting depolarizations (up to 10 sec) usually no tonic responses occurred. 5. A muscle once activated by a suprathreshold square clamp did not respond to a second depolarization unless the membrane had been repolarized to a given level and for a given duration. The amplitude of contractile response to second clamp steps depended in a characteristic manner on both the voltage and the duration of the recovery period. 6. Mechanical transients typically observed when either the voltage or the duration of clamp steps had been changed were analyzed in order to obtain information about the kinetics of intracellular Ca movements assumed to take place in a multicompartment model derived from structural and functional observations.