Showing papers on "Leakage (electronics) published in 1974"

Leakage current cancelling circuit for use with electrosurgical instrument

Abstract: Circuitry for cancelling leakage current is disclosed. The leakage cancelling circuit is utilized in conjunction wih the active or patient electrodes of an electrosurgical instrument used in electrosurgery. In electrosurgery, a radio frequency current is passed through a patient between an active electrode and a patient electrode with the active electrode determining the point where surgery is performed and the patient electrode being made surgically inactive by large patient contact area. Current leakage at the electrodes is caused by stray capacity to ground in an isolated system and excessive leakage from the active electrode to ground can cause surgery to be performed without a patient connection while excessive leakage from the patient electrode to ground can cause RF burns to the patient and perhaps to operating room personnel having contact with the patient. In one embodiment, current leakage is cancelled by addition of current to the patient connection in correct phase and magnitude to cancel the existing patient leakage currents, the added current being supplied through circuitry that includes a capacitor in series with the tertiary winding on the output power transformer supplying current to the active and patient electrodes. In a second embodiment, a series LC circuit is placed in parallel with the stray capacitance to cancel the same.

Radiation induced leakage current in N-channel SOS transistors

Abstract: High drain-leakage currents have been observed in n-channel SOS transistors after exposure to ionizing radiation. These currents could not be explained by the change in gate threshold voltage or by other radiation effects in the gate insulator. Two mechanisms were identified as being responsible for the radiation-induced leakage current. Charge trapping in the sapphire and the consequent formation of a channel at the silicon-sapphire interface is the major cause of the leakage current. Under some conditions, a smaller component of leakage current can also result from charge trapping in the silicon dioxide at island edges.

Conductor for reducing leakage at high frequencies

Abstract: Conductive wire coated with a thin magnetic film which is encircled by an insulating sheath. In various applications a plurality of said wires are wound together to provide a conductor having a low leakage due to eddy currents and dielectric leakage at certain frequencies.

Valve with heat transport monitor for leakage determining rate

Abstract: A valve having means for measuring leakage through the valve. The valve body has a small heater in the leakage flow path downstream of the upstream seal and a heat sensor upstream of the downstream seal in the leakage path; fluid that leaks past the upstream seal is heated and its presence detected by the heat sensor which then indicates the fact that the valve is leaking.

Semiconductor device having electrically insulating barriers for surface leakage sensitive devices and method of forming

Abstract: A semiconductor device has a heavily doped semiconductor substrate with a lightly doped epitaxial layer overlying a surface of the substrate and of the same conductivity type as the substrate. Electrically insulating barriers extend from at least the surface of the epitaxial layer into the substrate so as to electrically isolate non-common areas of each surface leakage sensitive device within the epitaxial layer from the non-common areas of adjacent surface leakage sensitive devices.

Leakage current monitoring system and method

Abstract: A device is disclosed herein for monitoring a power system for the presence of faults thereon which cause leakage currents to ground. The device includes a test impedance and bridge switching means for connecting the test impedance in different combinations to a pair of power lines. A singe test impedance is connected in four different configurations to the power lines in sequence, and this cycle is continuously repeated. Currents are measured for each connection to determine whether or not a leakage or hazard current exists which results from a fault load on one or both power lines. The device includes control means for operating the test impedance switching means, and includes current level detecting means for providing an alarm indication in the event a predetermined hazard current exists.

Electronic pressure cycle indicator

Abstract: Fluid pressure sensing means for sensing lubricant pressure levels. Means are activated to turn on a pump at regular intervals to provide lubrication at such intervals. It is desired to indicate failure of subsequent operation of the pump after a time interval greater in duration than the aforesaid periodic intervals. Pump operation causes closure of pressure switch which causes capacitance means to charge during the switch closure interval. As soon as the capacitance is charged beyond a predetermined threshold level, bistable means are set which in turn sets up a discharge path for the capacitor. The long-time constant of the discharge path, which is adjustable and which typically may be of the order of hours, continues until the voltage across the capacitor drops below a second predetermined threshold level resetting the bistable flip-flop. The reset operation triggers a switch means for illuminating a lamp which indicates that a prolonged period of time has occurred since the last pump operation. Recharging of the capacitance does not occur until the pressure switch again undergoes a switch closure operation which automatically sets the bistable flip-flop and turns the lamp off. Operation of the circuitry so as to charge the capacitor rapidly and allow for a slow discharge rate serves to substantially reduce capacitance leakage problems.

Element and method for detecting leakage of petroleum products

Abstract: A styrene-butadiene-styrene block copolymer containing 50 to 70% by weight of butadiene can be used as a base material of an element capable of detecting leakage of petroleum products by detecting to the change in an electrical signal. By use of this detecting element any leakage of petroleum products from a transportation pipe line may be detected and located quickly and precisely.

Rapid annealing in irradiated CMOS transistors

Abstract: Data characterizing the transient annealing of the gate threshold voltage of contemporary CMOS transistors following exposure to pulsed ionizing radiation are presented and discussed. Devices tested during the study include those fabricated on both bulk silicon and silicon-on-sapphire substrates. Silicon dioxide and aluminum oxide gate dielectrics are evaluated. Leakage current phenomena associated with charge formation in dielectric substrates or dielectric isolation layers are also considered.

Leakage and continuity tester

Abstract: A leakage and continuity test unit for checking the ground impedance and leakage current in a medical instrument to ensure that the medical instrument is properly grounded and does not conduct an excessive amount of leakage current through the chassis. The unit includes a test probe which is interconnected with the equipment under test, the unit including a continuity circuit having a comparator which compares a fixed voltage with a voltage representative of the impedance to ground of the equipment under test. The output of the comparator is fed to a flip flop circuit which, when an excessive amount of ground impedance exists, drives a warning lamp circuit. If the impedance is below certain set limits, the flip flop will drive a lamp which indicates that the ground of the equipment under test is proper. The unit also includes a leakage detector circuit which includes an upper and lower limit control circuit which establishes different standards for the equipment under test depending on whether the equipment is to be used in critical service or general service areas within the hospital. The leakage signal is fed through a precision rectifier which in turn feeds the signal to a dual input comparator which dual input comparator is capable of testing either a positive or negative signal. The output of the comparator is fed to a flip flop circuit which drives a set of lamps, one of which warns the user that an excess of leakage current exists and the other of which indicates to the user that the leakage current is within the limit set by the gain control circuit.

Electric battery with multi-cell stack isolation

Abstract: A construction which minimizes damage to alkaline electrolyte batteries due to electrolyte leakage caused by extreme variations in temperature is disclosed. The batteries comprise a multiplicity of individually sealed cells, arranged in electrically connected stacks, each stack being disposed in a moisture-proof plastic container and/or cup filled with an encapsulating resin in the entire space within the cup, with the encapsulated assembly being housed in a metal outer container. The cells within each stack and each stack itself is thus isolated, thereby minimizing any damage that might result from inter-cell leakage, from interstack leakage, and from leakage that would corrosively affect associated equipment in an assembled apparatus, due to extreme temperature variations, especially under high humidity conditions.

The role of radiation damage on the current-voltage characteristics of p-n junctions

Abstract: The effects of radiation damage on the current-voltage characteristics of silicon p-n diodes are studied. Radiation damage is introduced by the implantation of carbon ions into the depletion region of the device. The physical properties of the damage centres are examined by means of thermally stimulated current (T. S. C.) measurements, and by the measurement of the temperature dependence of the reverse leakage. The results at low implantation doses are explained by means of a single level Shockley-Read-Hall model, while at higher doses charge compensation effects are introduced. Capacitance-voltage measurements are used as a means of verifying these conclusions, and further useful data is obtained from the results of low temperature annealing experiments.

Protective diode network for MOS devices

Abstract: A protective diode network for a differential amplifier comprised of insulated gate field effect transistors. The network provides for both gate-to-gate and gate-to-source protection using a small number of components with minimal capacitive and leakage loading.

Method to improve the reverse leakage characteristics in metal semiconductor contacts

Abstract: A method for improving the reverse leakage characteristics in metal semiconductor contact devices is disclosed. The process embodies ionic plasma bombardment as a step in producing improved reverse bias current voltage characteristics between metal semiconductor contacts.

Discharge lamp lighting apparatus

Abstract: A discharge lamp lighting apparatus wherein a discharge lamp circuit is provided on the secondary side of a leakage transformer, the leakage transformer being arranged to produce a secondary voltage which is lower than the ordinary starting voltage of the discharge lamp. An auxiliary winding magnetically coupled with at least the secondary side winding of the leakage transformer is wound on an iron core, and a phase advancing current circuit is coupled to the auxiliary winding for raising the lamp voltage at turn-on to a level exceeding the starting voltage.

Techniques in Failure Analysis of MOS Devices

Abstract: The greatest concern on MOB devices is the physical integrity of the gate oxide. Leakage paths and/or shorts through defect sites in the oxide are a major device reliability problem. Optical microscopy is tedious and often does not resolve the defects. With this in mind, copper decoration techniques were developed that could reveal oxide failures sites down to 0.1?m size. The technique has isolated various failure mechanisms on MOS devices. This failure analysis capability has enhanced the ability to control the MOS process.

Leakage and h FE degradation in microwave bipolar transistors

Abstract: The phenomenon of h FE degradation due to an excessive reverse collector bias voltage has been investigated. The correlation between this h FE degradation phenomenon and the anomalously high collector leakage currents has been established. A model based on channels arising from diffusion induced pipes and spikes is presented. The model successfully explains these phenomena as observed in shallow-diffused microwave transistors.

Measurements on a charge-coupled area image sensor with blooming suppression

Abstract: Blooming, the lateral spreading of charge from an intensely illuminated area of an image sensor, can be present in an especially objectionable form in charge-coupled devices. Bright lines are formed in the display, owing to a charge propagation along the transfer channels. The introduction of overflow drains, i.e., stripes of a reverse-biased p-n junction placed between the transfer channels, provides a well-defined leakage path for excess carriers from saturated potential wells. An implanted threshold barrier between these drains and the integrating potential wells determines the saturation potential of the integration sites and prevents the total collapse of the associated depletion region. Therefore, the lateral diffusion of minority carriers is also greatly reduced. An existing design of a charge-coupled area image sensor with 64 × 106 resolution elements and frame transfer organization has been modified to study these methods of blooming suppression. The lateral distance of charge spreading has been reduced by a factor of seven at overload conditions of 20 dB. For stronger overloads the booming suppression becomes even more striking, but the performance of the device iS limited by frame transfer smearing. Furthermore, lens flare limits most optical systems at overloads above 30 dB. However, by using an optical fiber, well-localized overloads of 50 dB could be generated. Although, in our particular test device, the addition of blooming suppression reduced the light sensitivity by a factor of four, other geometries for overflow drain structures that should result in only a negligible loss in sensitivity are discussed.

Method of forming P-N junction in PbSnTe and photovoltaic infrared detector provided thereby

Abstract: This disclosure is directed to a method of forming a P-N junction in PbSnTe material in providing an infrared radiation diode detector, wherein signal radiation is absorbed in a low carrier concentration n-layer such that a Burstein Shift is not exhibited, while the bulk of the P-N junction is p-type material of high carrier concentration to prevent surface inversion. The method employs diffusion of a defect compensating impurity such as cadmium or zinc into unannealed PbSnTe material dominated by n-type background impurities. The diffusion of cadmium or zinc has a compensating effect on the p-type stoichiometric defects found in unannealed PbSnTe which results in a substantial reduction in the adverse effect of surface inversion layers and surface leakage, thereby achieving an improved operating performance from PbSnTe photovoltaic detectors so made.

Impatt diode testing

Abstract: A pulse technique and network are described for measuring the reverse leakage current of an operating IMPATT diode. Observation under substantially operating conditions is attained by pulsing the diode under test out of the avalanche condition very briefly and observing the reverse leakage current. High reverse leakage currents under these conditions indicate likelihood of ''''short out'''' failure.

Method and system for determining the resistance of the dielectric in a capacitor

Abstract: A rapid and accurate indication of the resistance of the dielectric in a capacitor with respect to a minimum acceptable value is obtained by connecting the capacitor in a feedback circuit of a high gain amplifier between an output and an input thereof. Initially, the capacitor is rapidly charged through a variable resistance connected to the input of the amplifier, until the charge on the capacitor is equal to a set value, such as its rated voltage. The variable resistance then is abruptly increased to a predetermined value that will maintain the charge on an acceptable capacitor at the set charge value. The voltage output of the amplifier then is monitored to ascertain stability, further charging or discharging of the capacitor, to provide an indication as to whether the capacitor''s dielectric resistance is at, above or below the minimum acceptable value, respectively.

Device for testing any leakage of vacuum-tight glass seals

Abstract: In a device for testing any leakage of vacuum-tight glass seals by means of high voltage electrodes arranged on either side of the glass seal, according to the invention at least one of the electrodes consists of a hot gas jet the burner of which is connected at one end to the high voltage source.

Toroidal electrolytic angle transducer

Abstract: A toroidal electrolyte-type angular transducer is provided for measuring angular displacement or tilt from a vertical plane. Three conducting paths in the electrolyte are established between two measuring electrodes and an auxilliary electrode respectively and a common electrode. Angular displacement is simply related to the values of the conductances in the various paths. In a preferred embodiment of the invention several guard-ring electrodes are included to divert spurious leakage currents from the common electrode so that the leakage current will not affect the measurement. The guard-ring electrodes are maintained at the same potential appearing at the collector electrode to ensure that no leakage currents pass between the two. Another preferred embodiment the invention provides that the two measuring electrodes are driven by voltages equal in magnitude and opposite in sign. A high gain operational amplifier is interconnected between the auxiliary electrode and the common electrode. By means of this arrangement a single voltage reading may be obtained which is directly proportional to angular displacement.

Apparatus for measuring coolant leakage in electrical power generating machines

Abstract: In an electrical power generating machine employing several coolant streams employing a water stream to cool the stator and a gaseous stream for cooling the machine housing. One of the two coolants is supplied with a coolant leakage indicating medium such as helium or tritium, such that, the presence of a coolant leak is ascertained by the passage of the leakage indicating medium from one coolant stream to another and is thereafter detected. A measuring device such as an iostope counter, is employed to measure the amount of indicating medium that is transferred due to leakage.

Method and means for indicating a leakage through the wall of a vessel

Abstract: Leakage through a fraction of the wall of a vessel is indicated by delimiting, at one side of the wall fraction, a narrow closed space connected to pressure measuring means, whereupon both sides of the wall of the vessel, except the area enclosed in the narrow space, are subjected to a similar gas pressure higher than the pressure within the space.

Electrical leads for low conductivity measurements under hydrostatic pressure

Abstract: An electrode system using sapphire for the low conductivity measurement under hydrostatic pressure below 5000 bar is described. The leakage resistance of this design is 1.3×1016Ω at 1000 bar, and 6×1014Ω at 4000 bar.

Analysis of leakage and friction factors in coal mine ventilation systems. Special research report number SR-99

Abstract: A critical review of previous studies in the area of leakage and friction factors has been made. The need for new friction factors and leakage characteristics is emphasized and theoretical considerations for their determination discussed. Results of preliminary investigations carried out are analyzed and discussed there is a general decrease in the value of friction factors as compared with McElroy's figures in roofbolted, fast moving, roadways in coal mines; there is a need to do additional work on friction factors for present day coal mines; and additional work is advocated for bolted returns and intakes taking into consideration the movement of the trains. Leakage studies show the pressure difference across a stopping has the greatest influence on leakage through stoppings; leakage losses are higher in the section of the airway furtherest from the working face; generally three quarters of the total loss occurs in the first half of the intake; and leakages are not the same in every mine. In recent years, there have been relatively few systematic studies regarding leakage and friction factors. An attempt has been made here to recognize leakages more effectively and to develop a leakage gradient which will help in ventilation network planning. (LTN)

Monolithic-IC telephone crosspoint subsystems

Abstract: A monolithic integrated crosspoint subsystem which includes 8 air-isolated SCR switches with associated switching and sensing circuitry on the central mother chip, will be discussed. Stringent telephone-system specifications have been achieved with negligible parasitic leakage and standby power.