Showing papers on "Electrode array published in 1969"

Electrographic imaging system and heads therefor

Abstract: An electrographic imaging system is provided for producing an electrostatic latent image upon an electrographic record medium having dielectric and conductive layers. Electrostatic charging means are provided comprising an array of charging electrode means, some of which are interconnected and thereby are connected to fewer first voltage source means than the total number of charging electrode means in the array. Also provided is an array of complementary electrode means which is connected to second voltage source means. The energized complementary electrode means are capacitively coupled to the conductive layer of the record medium to change the potential thereof upon a voltage pulse being applied to the complementary electrode means. The energized charging electrode means charge discrete areas of the dielectric layer of the record medium only when the complementary electrode means simultaneously are connected to the second source of voltage to effect the capacitive coupling. Also, heads are provided wherein an array of small electrical conductors is supported in a dielectric material in closely spaced relation to each other with the end faces thereof exposed and substantially flush with the support. Complementary electrode means are mounted on the support adjacent to but spaced from the end faces of the electrical conductors and form with the support means a substantially flush, smooth surface over which the record medium can move. Electrical Contacts for both the small electrical conductors and the complementary electrodes are provided in the support.

Ignition and flame detection system utilizing a single electrode

Abstract: A single electrode is positioned adjacent a burner in a furnace. A single circuit supplies current to create an arc across the electrode to the burner to ignite the furnace. The same circuit detects a DC current from the electrode to the burner due to the electric conductivity of the flame. The circuit includes means to shunt any AC current from the detector. An insulation material covers the electrode adjacent the arc-creating end to stabilize the DC current.

Laser‐Machining Thin‐Film Electrode Arrays on Quartz Crystal Substrates

Abstract: The feasibility of laser‐machining quartz crystal resonators for frequency and inter‐resonator coupling adjustment has been demonstrated. The inter‐resonator coupling has been adjusted by altering the geometry of the electrode array. The frequency has been adjusted by vaporizing material to form an array of holes on the electrode surface. The results indicate that extremely fine adjustments of inter‐resonator coupling and resonator frequency can be achieved. Frequency adjustments greater than one part in 108 have been demonstrated. No degradation of the crystal unit electrical parameters could be detected as a result of the machining process. Furthermore, laser trimming lends itself to automated processing without the need for elaborate vacuum equipment as is presently required with some adjustment techniques. Laser trimming also appears to be ideally suited for adjustment of high‐frequency resonators where fine tolerances are required.

High-pressure electric discharge lamp having electrolysis-preventing means

Abstract: The arc tube of an arc discharge lamp has two main electrodes and a starter electrode adjacent one of them, the starter electrode being electrically connected to the adjacent electrode through a resistor external of the arc tube. The starter electrode is electrically connected to the other main electrode through a thermally operative switch and a second resistor. In normal operation, the switch opens after lamp ignition to isolate the starter electrode from the circuit of the other main electrode and to place the starter electrode at substantially the same potential as the adjacent main electrode.

Measuring cell for measuring electrical conductivity of a fluid medium

Abstract: A measuring cell having current electrodes and voltage electrodes, the current electrodes being serially connected to an alternating current source and a current measuring device and the voltage electrodes being connected to a voltage measuring device whereby the ratio of the measured current flow to the measured voltage is a unique value indicative of the electrolytic conductivity of the medium. Electrical insulating means are positioned adjacent the voltage electrodes to effectively bypass the current flow around the voltage electrodes thereby screening same from the current flow. The insulating means prevents contamination and polarization of the voltage electrodes by the current flow whereby an accurate current measurement and voltage measurement is obtained.

High-pressure metal halide electric discharge lamp

Abstract: The arc tube of an arc discharge lamp has two main electrodes and a starter electrode adjacent one of them, the starter electrode being electrically connected to the adjacent electrode through a rectifying device, such as a diode, external of the arc tube. The polarity of the rectifier is such as to permit the starter electrode to attain a voltage positive with respect to the adjacent electrode but to substantially prevent a negative voltage therebetween.

Particle acceleration tube having improved beam focus control

Abstract: Improved focusing of a beam of charged particles is achieved in an acceleration tube comprising alternate insulating rings and apertured electrodes to which progressively increasing electric potentials are applied to create an electric field for accelerating the charged particles along the length of the tube. In order to achieve precise beam focusing for different electric field strengths the aperture of the grounded electrode at the tube entrance is covered with a grid-like structure and a variable control voltage is applied to a downstream control electrode. For different field strengths the control voltage is adjusted to modify the field between the grounded and control electrodes to provide a variable lens effect. A preferred embodiment employs a variable resistor connected between the grounded and control electrodes to provide the variable control voltage.

Polarity independent preamplifier for sound transmitters

Abstract: A preamplifier for sound transmitters includes at least one field effect transistor having a gate electrode and first and second output electrodes. An output circuit is connected across the output electrodes, a first output electrode resistor is connected between a feed voltage input terminal and the first output electrode and a second output electrode resistor is connected between a reference potential terminal and the second output electrode. The output electrode resistors have substantially the same resistance. A polarity dependent biasing circuit is connected between the feed voltage input terminal and the gate electrode, and maintains, at the gate, substantially a predetermined negative bias potential relative to the potential at the first output electrode if a potential which is negative by a predetermined amount relative to the potential at the reference potential terminal is applied to the feed voltage input terminal, and relative to the potential at the second output electrode if a potential which is positive by the predetermined amount relative to the potential at the reference potential terminal is applied to the feed voltage input terminal.

Triggered spark gap device

Abstract: A triggered spark gap device as disclosed which is adapted to switch exceedingly high values of voltage and current over a large dynamic operating range. The device comprises first and second main electrodes defining a main gap and an auxiliary electrode defining a trigger gap with one of the main electrodes. The auxiliary electrode is electrically isolated from the main electrode as a separate discharge path and means are provided to limit the discharge current therethrough thereby minimizing deterioration of the auxiliary electrode under the influence of high-discharge current. Additionally, the auxiliary electrode is provided with means for preventing induced circulating currents to avoid excessive heating and deterioration thereof. In a preferred embodiment the dynamic range is extended by biasing the auxiliary electrode with reference to one of the main electrodes so that it may be positioned closer to the other main electrode to obtain reliable firing at low-main gap voltage. Additionally, the other main electrode may be provided with an auxiliary electrode for electric field forming to increase the upper limit of the dynamic range.

Performance Characteristics of an MHD Power Generator with Seeding Plane and Staggered Electrodes

Abstract: This paper deals with a theoretical investigation on the influences of the seeding position and the electrode staggering on the electrical performance characteristics of a Faraday-type MHD power generator. The analysis was made by means of conformal mapping techniques. The results revealed the following: 1. The influences in question can be expressed by a parameter determined uniquely by the generator geometry. 2. The internal resistance of the generator is independent of the direction of the electrode staggering. 3. There exists a value of stagger at which the internal resistance is minimized for a finite seeding aspect ratio. 4. The electric current concentration on the electrode edge can be attenuated by suitably staggering the electrode. 5. Generators with a single electrode pair and those with segmented electrodes have quite similar current density profile on the electrode surfaces, but rather different distribution on the generator center line.

Heavy duty overvoltage power gap

Abstract: A main power gap has a combined heat shield and arc controlling trigger electrode, there being a resistive voltage grading network connected between the main electrodes and the trigger electrode, with an accurately calibrated voltage-responsive pilot gap connected between one main electrode and the trigger electrode.

Circuit arrangements for pulsing the control current of a hall generator

Abstract: A pulse generator circuit includes a unijunction transistor having an emitter electrode connected to a common point in the connection between the resistor and capacitor of an RC circuit, a base 1 electrode, a base 2 electrode and an interbase path. A Hall generator is connected in series with the unijunction transistor via the interbase path of the transistor and has one control current electrode connected to the base 1 electrode of the unijunction transistor, another control current electrode connected to the capacitor of the RC circuit, one Hall voltage electrode connected to the negative polarity terminal of a source of DC voltage and another Hall voltage electrode galvanically connected to the control circuit of an electronic switching component.

Electrochemical Characterization of Mass Transport at Microelectrode Arrays

Abstract: Electrodes with dimensions in the micro- and nano-meter scale can be used as analytical probes in confi ned places such as cells and organelles. Arrays of microelectrodes, particularly disk-shaped electrodes, are now a platform to fabricate electrochemical sensors and multisensors. A useful characteristic of such arrays is that enhancement of the current signal is due to the fact that radial diffusion becomes important as the disk radius gets smaller and steady state currents are attainable in a relatively short time. Because there is no general analytical solution for the current response at MEAs, previous characterization of any micro electrode array at hand is still required. This paper discusses the electrochemical characterization of the mass transport of a reversible electrochemical probe at a commercially available micro-disk electrode array by two commonly used tools for electro analysis, namely: cyclic voltammetry and chronoamperometry. The questions to be addressed are whether clear radial diffusion control can be effectively achieved and the time required for the electrode system to reach steady state. For chronoamperometric experiments, the current response almost achieves steady state in the time range between 0.49 s and 1 s. This is precisely the time bracket in which analytical measurements should be made in order to achieve high sensitivity.