Showing papers on "Low voltage published in 1978"

Control circuit for rear view mirrors provided with a liquid crystal cell

Abstract: An anti-dazzle rear view mirror incorporates a liquid crystal cell the conductive layers of which are energized by a control voltage in response to light above a threshold intensity impinging on a photoresistor in the control circuit of the cell. A low voltage source, for example a vehicle 12 volt battery, supplies a potential divider which includes the photoresistor, the voltage across which is connected through a logic invertor which controls two logic NAND gates for gating antiphase square wave outputs derived from an oscillator driven from the source to the respective conductive layers of the cell, thereby producing a square-wave voltage across the cell which is double the amplitude of the oscillator output, and decreasing the time taken for the liquid crystal cell to respond to the light intensity change.

Low voltage techniques

Abstract: Techniques for the design of linear ICs, capable of operating from a single nickel-cadmium cell (> 1.1V) will be presented. Results can be achieved without compromising performance or operation at higher voltages. Emphasis will be on micropower, though not at the expense of output drive.

Low voltage techniques [for micropower operational amplifiers]

Abstract: A micropower operational amplifier is described that will operate from a total supply voltage of 1.1 V. The complementary class-B output can swing within 10 mV of the supplies or deliver /spl plusmn/20 mA with 0.4 V saturation. Common mode range includes V/SUP -/, facilitating single-supply operation. Otherwise, DC performance compares favourably with that of the LM108. An adjustable-output voltage reference is also presented that uses a new technique to eliminate the bow usually found in the temperature characteristics of the band-gap reference. Minimum supply is 1 V, and typical drift is 0.002 percent//spl deg/C.

Dual-voltage electric hair curling apparatus and vanity case therefore

Abstract: A dual-voltage electric hair curling apparatus includes a having a handle and a heated barrel. A pair of positive temperature coefficient (PTC) heating elements are located in the barrel and are operable, respectively, at a low automotive vehicle voltage and a high domestic voltage. A switch in the handle permits energization of either heating element dependent upon the voltage of the available power supply and an overload fuse prevents damage to the low voltage heater should it be accidently energized from a high voltage supply. The curler is provided with a power cord terminating in a two-pronged plug receivable into a corresponding receptable on a portable vanity case adapted to be mounted by clips to the visor of an automotive vehicle. The vanity case has a mirror illuminated by electric luminaires on its front surface and a cord set terminating in a plug receivable in an automobile cigar lighter is connected to the receptable and luminaires. When not in use the hair curler, power cord and cord set are stored in a compartment in the vanity.

Integral relay low voltage retentive means

Abstract: An electromagnetic relay is provided with a high current "boost" coil, a lower current normal operating or "seal" coil and a static, electronic circuit that functions under low voltage conditions to energize the boost coil to retain the relay closed. An additional function of this static, electronic circuit is to energize the boost coil for a time interval on initial power application in order to assist in closing the relay, and this time interval automatically varies in the correct direction with variation in the supply voltage available to the coil so that the lower such available voltage is from its normal value, the longer the boosting time interval. At other times, both coils are energized in series at low current to hold the relay closed. This static, electronic circuit is small enough to be integrally incorporated within the housing of a conventional sealed power relay.

Integrated semiconductor memory array having improved logic latch circuitry

Abstract: There is described a logic element employing fixed threshold and variable threshold transistors electrically connected together in a unique manner to form a latch. The latch can be made to retain data by keeping certain internal nodes at a high or low voltage level. As such it acts as an ordinary semiconductor memory latch, whose data can be changed by externally overriding the internal voltage levels of the latch cell. The novel results of the cell described are achieved by replacing one or several of the transistors in the latch by specially constructed transistors, whose threshold voltage can be raised or lowered upon application of a relatively high voltage pulse between their gate and substrate. By application of such a high voltage pulse, the data stored in the latch can be translated into controlled threshold shifts of the variable threshold transistors, which uniquely represent the initial latch state. Therefore, if power is removed and then returned, the latch will always settle into a state dictated by the final state that existed in the latch before the high voltage pulse was applied. In this way the variable threshold elements of the latch cell make it a non-volatile memory element. It can be used either as a read/write memory, using its latch property, or as a read-only memory, using the variable threshold transistors to cause it to always latch in a predetermined manner.

Power supply system

Abstract: An electrical control system containing a power supply network including a primary high voltage power source and a secondary low voltage power source, the primary power source being held inactive except for periodic intervals of time, and also being removable for replacement or recharging; the secondary power source being charged during operation of the primary power source and being operative while the primary power source is inoperative.

High voltage CMOS level shifter

Abstract: A reliable voltage level shifter circuit implemented with complementary metal oxide semiconductor field effect transistor (MOSFET) devices, suitable for high voltage applications. The disclosed circuit is relatively unsusceptible to low voltage transistor breakdown, whereby a wide range output voltage swing is achieved.

Protective circuit for zinc oxide varistors

Abstract: The invention provides a circuit for determining excessive energy magnitudes or rates of rise of energy in metal oxide varistor devices. The circuit further provides a series of low voltage control pulses for energizing a high voltage pulse generator. The output of the high voltage pulse generator triggers a protective air gap for bypassing the metal oxide varistor device. One application for the invention is for use within a series capacitor protective circuit.

Driver circuitry for plasma display panel

Abstract: Sustainer drive circuitry for an AC plasma display panel wherein a multiple level sustainer signal is applied to panel electrodes along one axis only The sustainer circuit includes a pair of series connected NPN pull-high and pull-down output driver transistors which (a) are respectively driven by low voltage drive circuits isolated from the NPN output driver transistors by capacitors; (b) respectively charge up the panel to a relatively high voltage and discharge the panel to ground; and (c) include a feedback network for limiting the rise time of the high voltage across the panel for reducing noise and electromagnetic interference Diode circuitry insures that these output driver transistors are turned on and off without ringing and are never driven on simultaneously A common voltage supply provides both (a) the write pulse level and (b) the write pedestal level of the sustainer waveform The invention further provides a border sustain driver circuit for one axis which comprises simple and inexpensive integrated circuit logic gates

Induction heating device

Abstract: PURPOSE:To prevent an output element from destroying in case a work to be heated is inadequate in a state of preparation, by feeding a low voltage in an output circuit and detecting a damper current of the circuit.

Sense line termination circuit for semiconductor memory systems

Abstract: A sense line termination circuit is provided intercoupled between a sense line of a plurality of static memory cells and a supply bus of high pull-up voltage to provide fast access to the memory cells with limited medium power dissipation. The termination circuit functions to pull up the sense line toward a predetermined intermediate high voltage value (which is about one threshold voltage Vt below the high pull-up voltage) when no memory cell has a low voltage memory node coupled to the sense line. The sense line termination circuit limits the voltage excursion of the sense lines and also permits the sense line to be pulled down with predetermined current limitation to a low voltage value when the sense line is coupled to a low voltage memory node. In a preferred embodiment, the sense line termination circuit comprises an enhancement mode FET device whose drain and gate are connected to the supply bus and whose source is connected in series with the drain of a depletion mode FET device whose source is connected to the sense line and whose gate may be connected to the same sense line or to other suitable gate bias voltage sources. The enhancement device has a substantially constant voltage drop across it from the pull-up supply voltage to the intermediate voltage, and substantially all the voltage variations between pull-up and pull-down occur across the depletion device. The enhancement device is preferably substantially larger in size and current carrying capacity than its corresponding depletion device.

Programmable transistor read only memory - has integrated matrix structure operating with low voltage pulses

Abstract: A programmable read-only memory has integrated bipolar transistors. It is fast, small in size, used with logic circuits and programmable with low voltage pulses. The memory comprises a matrix of rows and columns, and NPN transistors. Each row of the matrix is made up of interconnections of the collectors (11) of a row of transistors, each row being insulated from the next row. Each column is made up of interconnections (18, 18a) of the emitters (15) of a column of transistors. The superimposed emitter-base (15, 14) and base-collector (14, 11) junctions of each transistor are in layers of the semi-conductor material (1, 2). The emitter (15) and the base (14) are limited by the same face of an insulating strip (17).

Low voltage distribution system for miniature structure

Abstract: A low voltage distribution system for a miniature structure having a step down transformer which is energized from a high voltage alternating current source to produce a low voltage signal, a pair of elongated bus bar strips formed of a conductive metal foil layer and an adhesive bottom layer which is used to affix the bus bar to the miniature structure with the bus bars being positioned in a spaced parallel relationship, electrical conductors for applying the low voltage signal across the spaced parallel bus bar strips, a plurality of bi-prong electrical fastening devices which have sharp ends to pierce and drive through the bus bar strips forming an electrical connection therewith and into holding relationship with the section of the miniature structure under the bus bar strips and a plurality of light bulbs electrically connected across the bi-prong electrical fastening devices wherein the light bulbs are responsive to the low voltage signal to become illuminated is shown.

High current low voltage liquid cooled switching regulator DC power supply

Abstract: An improved high current low voltage switching regulator power supply in which the major heat producing components of the power modules of the power supply are mounted on a pair of chill plates with a liquid cooled heat exchanger between the plates. The chill plates are electrically isolated from each other and the heat exchanger. One chill plate also serves as the positive power output bus and the other as the negative power output bus of the power supply which significantly reduces the parasitic inductance of the power supply.

Ground fault protection system for industrial power circuits

Abstract: A ground fault circuit interrupting (GFCI) device of the type utilized in low voltage, residential type circuits for personnel protection against ground faults is connected in circuit with a high voltage, high current source so as to trip in response to ground fault current returning to the source via a conductor path solidly connecting the source to ground.

Low voltage hard anodizing process

Abstract: A process for hard anodizing of aluminum and aluminum alloys by use of a low voltage having a DC component and a superimposed AC component. The electrolyte can have relatively low acid concentration and can be of higher temperature than usually employed for hard anodizing.

Method of manufacturing a low voltage n-channel MOSFET device

Abstract: A novel MOSFET circuit and method of manufacture utilizing a double ion implant process for manufacturing a low voltage high performance n-channel device that includes an enhancement transistor inverter combined with a depletion transistor load. The process starts with high resistivity material and uses a first ion implant process to dope the field region and to give the required threshold voltage for an enhancement device. A second ion implant is used to dope the channel region for the depletion device.

D.C. to D.C. Converter utilizing resonant inductor to neutralize capacitive losses

Abstract: A d-c to d-c converter utilizing a resonant inductor to neutralize capacitive losses is disclosed. In most high voltage d-c power supplies, a step-up transformer is employed as the conversion element from the low voltage source to the high voltage output. Such transformers exhibit capacitive losses resulting from intra-and inter-winding capacitances. When utilizing a large step-up transformer wherein the turns ratio n=N p /N s is much less than 1, the capacitive losses result in a sharp decrease in the load to source voltage ratio thereby reducing the power available to the load. The present invention compensates for these losses by providing a resonant inductor which forms, at the operating frequency of the transformer, a resonant circuit with the equivalent Thevenin capacitive reactance as viewed from the primary side of the transformer resulting from these losses.

Low voltage vacuum switch and operating mechanism

Abstract: A low voltage vacuum switch and operating mechanism is detailed which is readily used as a shorting switch arrangement in electrolytic cells between the high current carrying bus bars of the cell. The switch has a very low profile and axial contact travel distance and is opened and closed by a means which translates rotational motion to a generally axial contact movement via a cam and connecting member, with overtravel dished washer spring means provided to keep the contacts closed until a positive opening force is applied. The low voltage vacuum shorting switch is detailed with axially movable non-weld contacts. The switch has a compact, rugged design for use in low voltage, high current severe environment application. A pair of thin flexible annular members having annular corrugations formed therein permit axial movement of the contacts.

High and low voltage measuring apparatus employing a single display and impedance matching

Abstract: Apparatus for measuring a high voltage in an ignition circuit, in which voltage dividing means has a first arm for connection to a point of measurement in said circuit and a second arm connected to a rectifying means. The output of the rectifying means is connected to means for matching impedance at the rectifying means to a direct current voltage display means connected to the output of the impedance matching means such that a displayed voltage is related to the high voltage in the ignition circuit. Low voltage measuring circuitry is also present which is connectable directly to the display means without the use of an impedance matching circuit.

Dental X-ray apparatus

Abstract: In dental x-ray apparatus a control is provided for driving the high voltage transformer in the tube head at a frequency far above power line frequency. The transformer is driven with an inverter. A precision d-c voltage regulator that operates in an "add-on" mode and thus only handles a portion of the output current controls the voltage supplied to the inverter. The d-c voltage regulator is supplied a voltage by a transformerless a-c/d-c converter whose output is proportional to the 60 Hz power line voltage that supplies it. The x-ray tube filament transformer is also driven at a frequency above power line frequency. Means are provided to cut off power to the x-ray tube if its current does not reach a certain value within a short time after an exposure is initiated. Means are provided for isolating high voltage power circuits from low voltage control circuits.

Regulated dual DC power supply

Abstract: A dual section power supply, one section for supplying high voltage dc po and the other section for supplying low voltage dc power, are each connected to a common ac source. The high voltage section employs a phase-controlled rectifier, the control circuit for which employs logic signal development using timer techniques dependent on the amplitude of voltage deviation from the intended regulated output level. Each of two low voltage sections employs a power switch controlled by sampling and pulse steering techniques to effect fixed high frequency, variable duty cycle switching. An inhibit input is supplied from each of the low voltage sections to the high voltage section to prevent a high voltage output to the load in the absence of low voltage development.

Buffered high frequency plasma display system

Abstract: A plasma discharge display device is operated at a high frequency above the response range of the inherent wall charge storage phenomenon and utilizes a refresh buffer. The vertical drive selection includes a pair of shift registers operated in parallel into which data from the host or associated controller is loaded, with an individual driver associated with each register stage. The horizontal lines are addressed through associated shift registers in an even-odd interlace sequence to generate a display on a horizontal scan basis. The horizontal drivers are referenced at the level and frequency of the high frequency energizing signals, while the vertical drivers are selectively set to ground or a positive a.c. voltage according to the state of associated register cells. By using the high frequency signal in the horizontal axis as a floating reference and unique selection techniques, the display is operated by low voltage signals. The normal sustain and erase operations associated with conventional plasma discharge devices are eliminated, while the write operation does not require either the precise timing or logical considerations associated with the selective operation of conventional plasma discharge display devices. The low voltage drive requirements permits use of low voltage driver circuitry which is susceptible to low cost monolithic fabrication techniques.

Ceramic Capacitor Insulation Resistance Failures Accelerated by Low Voltage

Abstract: Ceramic capacitors failed insulation resistance testing at less than 1/10th their rated voltage. Many failures recovered as the voltage was increased. Comprehensive failure analysis techniques, some of which are unprecedented, were used to examine these failures. It was determined that there was more than one failure mechanism, and the results indicate a need for special additional screening.

Pulse transformer technique for optical switch

Abstract: Optical communication apparatus is disclosed whereby the voltage controlled load device typically requiring a relatively high energizing voltage is operated by means of a wide band step-up pulse transformer and a low voltage power source. The step-up transformer permits operation of the fiber optic communication system from a power source as low as 5 volts D.C. to obtain the necessary modulation potential required by the electro-optic and piezoelectric load device.

Method and apparatus for adjusting the gap in an electric discharge machine

Abstract: Disclosed is an electric discharge machining method in which the electric discharge working gap between an electrode and a work piece to be machined is automatically adjusted. To detect the condition of the discharge working gap, a low voltage pulse is applied each time a plurality of high voltage pulse for electric discharge machining are applied for a predetermined time. The working current resulting from the application of each low voltage pulse is detected to control the feeding of the electrode and thereby to automatically adjust the discharge working gap to a predetermined value.

GaAs junction field effect transitors for low‐temperature environments

Abstract: Thermal, electrical, and noise characteristics of a GaAs junction FET are described. Low voltage noise [1.5±0.2 nV/(Hz)1/2 at T =4.2 K] and insensitivity to temperature change in the range 1.3⩽T ⩽300 K make it suitable for low‐temperature applications.

Differential amplifier circuit

Abstract: The transistors of a differential amplifier are coupled at their common emitter electrode connection to a low voltage power supply terminal and at their collector electrodes through respective current sinks to a point of reference potential. The collector electrodes are maintained at a voltage level above the reference potential to permit input signal swings at the base electrodes of the transistors a comparable amount below the reference voltage level. Current sources are provided for satisfying that portion of the current demand of these sinks not furnished by the transistors. When the amplifier is connected to operate as a voltage follower, additional transistors may be provided to prevent an undesirable change in the polarity of the output signal, when the input signal swings substantially below the reference voltage level.

Current mirror circuit

Abstract: PURPOSE:To secure the operation with a fixed current mirror ratio kept assuredly as well as to ensure the operation with the low voltage by preventing the base current of the transistors at the input and output sides from flowing to the constant current source. CONSTITUTION:Transistor Tr5 is driven by Tr4 connected directly to power source +B so that the base current of Tr1 and Tr2 of the input and output sides is prevented from being flown to constant current source 1. Thus, the ratio between current I1 flowing through source 1 and current I2 flowing through load 2, i.e., the current mirror ratio can be kept assuredly to secure the operation. And a small amount of current amplification rate hfe of Tr1 and Tr2 does not give any effect to the current mirror ratio at all. Furthermore, as the emitter of Tr4 is connected directly to source +B, the voltage between the emitter of Tr1 and the base of Tr4 turn to the inter-base and emitter voltage which can be driven with the low voltage.